Sample records for thin film superconductor

  1. Shielding superconductors with thin films

    E-print Network

    Posen, Sam; Catelani, Gianluigi; Liepe, Matthias U; Sethna, James P

    2015-01-01

    Determining the optimal arrangement of superconducting layers to withstand large amplitude AC magnetic fields is important for certain applications such as superconducting radiofrequency cavities. In this paper, we evaluate the shielding potential of the superconducting film/insulating film/superconductor (SIS') structure, a configuration that could provide benefits in screening large AC magnetic fields. After establishing that for high frequency magnetic fields, flux penetration must be avoided, the superheating field of the structure is calculated in the London limit both numerically and, for thin films, analytically. For intermediate film thicknesses and realistic material parameters we also solve numerically the Ginzburg-Landau equations. It is shown that a small enhancement of the superheating field is possible, on the order of a few percent, for the SIS' structure relative to a bulk superconductor of the film material, if the materials and thicknesses are chosen appropriately.

  2. Thin film growth of oxide superconductor materials

    SciTech Connect

    Henry, R.L.; Cukauskas, E.J.; Singer, A.H.; Campisi, G.G.; Qadri, S.B.

    1989-03-01

    Thin films of YBa/sub 2/Cui/sub 3/O/sub 7/, YBa/sub 2/Cu/sub 3/O/sub 7/:Ag,and Bi/sub 2/CaSr/sub 2/Cu/sub 2/O/sub 8/ have been grown by spray pyrolysis of aqueous nitrate solutions. Substrate temperatures in the range 300/sup 0/C to 875/sup 0/C have been investigated. Following deposition, the films were annealed in flowing oxygen at 960/sup 0/C for YBa/sub 2/Cu/sub 3/O/sub 7/ and 850/sup 0/C for Bi/sub 2/CaSr/sub 2/Cu/sub 2/O/sub 8/. The unit cell size of YBa/sub 2/Cu/sub 3/O/sub 7/:Ag did not change from that of YBa/sub 2/Cu/sub 3/O/sub 7/ but the X-ray diffraction patterns for the YBa/sub 2/Cu/sub 3/O/sub 7/:Ag films show that the (001) reflections are greatly enhanced over all others. A T/sub c/ of 81K with a ..delta..T/sub c/ of 3K has been measured for YBa/sub 2/Cu/sub 3/O/sub 7/:Ag films and a T/sub c/ of 74K with ..delta..T/sub c/ of 3K has been measured for YBa/sub 2/Cu/sub 3/O/sub 7/. These films were all grown on MgO substrate. The Bi/sub 2/CaSr/sub 2/Cu/sub 2/O/sub 8/ films are multiphase and have T/sub c/ of 65K with a very broad transition. The materials were characterized by X-ray diffractometry, scanning electron microscopy, and resistive superconducting transition measurements.

  3. Thin film superconductors and process for making same

    DOEpatents

    Nigrey, P.J.

    1988-01-21

    A process for the preparation of oxide superconductors from high-viscosity non-aqueous solution is described. Solutions of lanthanide nitrates, alkaline earth nitrates and copper nitrates in a 1:2:3 stoichiometric ratio, when added to ethylene glycol containing citric acid solutions, have been used to prepare highly viscous non-aqueous solutions of metal mixed nitrates-citrates. Thin films of these compositions are produced when a layer of the viscous solution is formed on a substrate and subjected to thermal decomposition.

  4. Superconductivity of very thin films: The superconductor-insulator transition

    NASA Astrophysics Data System (ADS)

    Lin, Yen-Hsiang; Nelson, J.; Goldman, A. M.

    2015-07-01

    The study of thin superconducting films has been an important component of the science of superconductivity for more than six decades. It played a major role in the development of currently accepted views of the macroscopic and microscopic nature of the superconducting state. In recent years the focus of research in the field has shifted to the study of ultrathin films and surface and interface layers. This has permitted the exploration of one of the important topics of condensed matter physics, the superconductor-insulator transition. This review will discuss this phenomenon as realized in the study of metallic films, cuprates, and metallic interfaces. These are in effect model systems for behaviors that may be found in more complex systems of contemporary interest.

  5. MICROWAVE PROPERTIES OF TUNABLE PHASE SHIFTER USING SUPERCONDUCTOR\\/FERROELECTRIC THIN FILMS

    Microsoft Academic Search

    MIN HWAN KWAK; YOUNG TAE KIM; SEUNG EON MOON; HAN-CHEOL RYU; SU-JAE LEE; KWANG YONG KANG

    2005-01-01

    High temperature superconductor, YBa2Cu3O7?? (YBCO), and ferroelectric, Ba0.1Sr0.9TiO3 (BST), multilayer thin films were deposited on MgO (100) substrates using a pulsed laser deposition. The thin films exhibited only (00l) peaks of YBCO and BST. The HTS thin films demonstrated excellent zero resistance temperature of 92.5 K. We designed and fabricated HTS ferroelectric phase shifter using high frequency system simulator and

  6. Discriminator Stabilized Superconductor/Ferroelectric Thin Film Local Oscillator

    NASA Technical Reports Server (NTRS)

    Romanofsky, Robert R. (Inventor); Miranda, Felix A. (Inventor)

    2000-01-01

    A tunable local oscillator with a tunable circuit that includes a resonator and a transistor as an active element for oscillation. Tuning of the circuit is achieved with an externally applied dc bias across coupled lines on the resonator. Preferably the resonator is a high temperature superconductor microstrip ring resonator with integral coupled lines formed over a thin film ferroelectric material. A directional coupler samples the output of the oscillator which is fed into a diplexer for determining whether the oscillator is performing at a desired frequency. The high-pass and lowpass outputs of the diplexer are connected to diodes respectively for inputting the sampled signals into a differential operational amplifier. The amplifier compares the sampled signals and emits an output signal if there is a difference between the resonant and crossover frequencies. Based on the sampled signal, a bias supplied to the ring resonator is either increased or decreased for raising or lowering the resonant frequency by decreasing or increasing, respectively, the dielectric constant of the ferroelectric.

  7. Sputter Deposition of Yttrium-Barium Superconductor and Strontium Titanium Oxide Barrier Layer Thin Films

    Microsoft Academic Search

    James Kelly Truman

    1992-01-01

    The commercial application of superconducting rm YBa_2Cu_3O_{7 -x} thin films requires the development of deposition methods which can be used to reproducibly deposit films with good superconducting properties on insulating and semiconducting substrates. Sputter deposition is the most popular method to fabricate Y-Ba-Cu-O superconductor thin films, but when used in the standard configuration suffers from a deviation between the compositions

  8. Molecular beam epitaxy deposited thin films of bismuth compound superconductors

    NASA Astrophysics Data System (ADS)

    Bernhoff, H.; Flodström, A. S.

    1990-08-01

    Thin films of superconducting BiCaSrCuO have been grown by molecular beam epitaxy depositions of Bi, Cu, and CaF2/SrF2 on MgO and SrTiO3 followed by a high-temperature oxygen anneal. The films showed a fairly wide transition of 20 K at a Tc of 80 K. Residual amounts of fluorine, detected with secondary-ion mass spectrometry, are believed to cause the broad superconducting transition. X-ray diffraction analysis of the superconducting films revealed strongly c-axis oriented films consisting of Bi2CaSr2Cu2O8 and Bi2Sr2Cu1O6 phase. Surface structure studies, with scanning electron microscopy and scanning tunneling microscopy, show oriented 1 ?m sized very smooth flat grains of superconducting phase in the plane of the film with islands of CuOx scattered on top of these.

  9. Molecular beam epitaxy deposited thin films of bismuth compound superconductors

    SciTech Connect

    Bernhoff, H.; Flodstroem, A.S. (Materials Science, Department of Physics, Royal Institute of Technology, S-100 44 Stockholm (Sweden))

    1990-08-13

    Thin films of superconducting BiCaSrCuO have been grown by molecular beam epitaxy depositions of Bi, Cu, and CaF{sub 2}/SrF{sub 2} on MgO and SrTiO{sub 3} followed by a high-temperature oxygen anneal. The films showed a fairly wide transition of 20 K at a {Tc} of 80 K. Residual amounts of fluorine, detected with secondary-ion mass spectrometry, are believed to cause the broad superconducting transition. X-ray diffraction analysis of the superconducting films revealed strongly {ital c}-axis oriented films consisting of Bi{sub 2}CaSr{sub 2}Cu{sub 2}O{sub 8} and Bi{sub 2}Sr{sub 2}Cu{sub 1}O{sub 6} phase. Surface structure studies, with scanning electron microscopy and scanning tunneling microscopy, show oriented 1 {mu}m sized very smooth flat grains of superconducting phase in the plane of the film with islands of CuO{sub {ital x}} scattered on top of these.

  10. Thermal treatment of superconductor thin film of the BSCCO system using domestic microwave oven

    NASA Astrophysics Data System (ADS)

    Silveira, J. B.; Carvalho, C. L.; Torsoni, G. B.; Aquino, H. A.; Zadorosny, R.

    2012-08-01

    In this work, we report the preparation of a superconductor thin film of the BSCCO system using a good quality powder with nominal composition Bi1.8Pb0.4Sr2CaCu2Ox which was thermally treated using a domestic microwave oven (2.45 GHz, 800 W). This film was grew on a single crystal of LaAlO3 (1 0 0) substrate and exhibited a crystalline structure with the c-axis perpendicular to the plane of the substrate. An onset superconducting transition temperature was measured at 80 K.

  11. Thin film growth of the 2122-phase of BCSCO superconductor with high degree of crystalline perfection

    NASA Technical Reports Server (NTRS)

    Raina, K. K.; Narayanan, S.; Pandey, R. K.

    1992-01-01

    Thin films of the 80 K-phase of BiCaSrCu-oxide superconductor having the composition of Bi2Ca1.05Sr2.1Cu2.19O(x) and high degree of crystalline perfection have been grown on c-axis oriented twin free single crystal substrates of NdGaO3. This has been achieved by carefully establishing the growth conditions of the LPE experiments. The temperature regime of 850 to 830 C and quenching of the specimens on the termination of the growth period are found to be pertinent for the growth of quasi-single crystalline superconducting BCSCO films on NdGaO3 substrates. The TEM analysis reveals a single crystalline nature of these films which exhibit 100 percent reflectivity in infrared regions at liquid nitrogen temperature.

  12. Processing And Patterning Of Thin Film Superconductors Formed By Metallo-Organic Deposition

    NASA Astrophysics Data System (ADS)

    Micheli, Adolph L.; Mantese, Joseph V.; Hamdi, Aboud H.

    1990-04-01

    Thin film superconductors of Y-Ba-Cu and Yb-Ba-Cu were formed by the pyrolysis of neodecanoate solutions of Y, Yb, Ba and Cu which had been deposited onto <100> SrTiO3 substrates [1]. Rapid thermal annealing, in oxygen, of the as-deposited films produced high T films having superconducting onset temperatures above 90 K and zero resistance at 8g K. Scanning Electron Microscopy (SEM) revealed enhancements in grain growth, compared to furnace annealed films, by a factor of 4. X-ray diffraction analysis showed preferred epitaxial grain growth with the c-axis of the films oriented both perpendicular and parallel to the substrate surface. Separate Rutherford Backscattering Spectrometry (RBS) channeling experiments confirmed the formation of preferred epitaxial grain growth. Film composition was determined by RBS and Inductively Coupled Plasma Emission Spectrometry (ICPES). Selective patterning was accomplished by focused beam exposure of the metal neodecanoate films [2-4]. The exposure rendered the neodecanoate film locally insoluble in xylene, thus permitting selective area patterning prior to pyrolysis. Electron, ion and laser beams were used to pattern films on <100> SrTiO3. The finest lines, approximately 5 #m in width and 26 nm thick, were patterned using electron beams whose lines had superconducting onsets above 90 K and zero resistance at 69 K after rapid thermal annealing. Both ion beam and laser patterning had similar superconducting onsets and zero resistance. Neodecanoates of Y, Yb, Ba, and Cu were formed, as previously described [5], by reacting the metal acetates of these materials with either ammonium neodecanoate or tetramethyl ammonium neodecanoate. The carboxylates formed from these reactions were then dissolved in a solution of xylene and pyridine. The individual chemical constituents were combined to produce solutions, Ln:Ba:Cu, in the ratio 1:2:4. Here, Ln is a rare-earth element. Details of the preparation of the metal carboxylates may be found elsewhere [6]. Thin films of Y-Ba-Cu and Yb-Ba-Cu were deposited onto <100> SrTiO by flooding the substrates with the appropriate neodecanoate solutions, then spin drying them at 2000 rpm for 30 s. The substrates were heated rapidly to 500?°C for 5 min in an air oven to pyrolize the metallo organics to their oxides. This process produces thin films about 200 nm thick. The spin coating process was repeated 3-6 times if thicker films were desired. X-ray diffraction analysis of films pyrolized at 500?°C shoed the presence of only microcrystallites. Room temperature resistivities of lx10 0-cm were measured for these films. No superconducting behavior was observed. After the 500?°C pyrolysis the films were further processed by RTA in flowing oxygen. The substrates were placed upon oxidized silicon wafers, rapidly heated to 850?°C for 60 s using infrared radiation produced by a bank of quartz lamps then allowed to cool to room temperature. A second rapid annealing was then performed at 920?°C for 30 s in oxygen. Thin film superconductors formed in the manner described above were very uniform in structure and thickness across the surface of the film. The grains are approximately 1 #m wide and 2 #m long, a factor of 4 larger than the grains found in furnace annealed films formed by MOD [5].

  13. Superconducting tunneling studies on thin film gold nanowires coupled to a BCS superconductor

    NASA Astrophysics Data System (ADS)

    Wei, Peng; Katmis, Ferhat; Chang, Cui-Zu; Lee, Patrick; Moodera, Jagadeesh

    2015-03-01

    The nanowire patterned out of (111)-oriented gold thin film is an excellent candidate for hosting Majorana bound states (MBS) when it is coupled to an s-wave superconductor. The robust MBS is guaranteed by the large Rashba spin-orbit coupling (SOC) of gold surface state, as well as by large spatial separations between the two MBS in fabricated micrometer size long nanowires. In addition, being able to produce complex nanowire circuit, our approach is better streamlined for achieving the braiding circuit of Majorana fermions. We present our experimental approach of growing high quality hetero-layers consisting of epitaxial (111)-oriented gold thin film on vanadium using molecular beam epitaxy (MBE). Unique lithography processes are developed to pattern the top gold thin film into nanowires with a width around 100nm without damaging the hetero-layers such as its topography or superconducting behavior. Superconductive tunneling studies are performed over the gold nanowire using lithographically fabricated planar tunnel junctions. These tunneling characteristics will be discussed. We acknowledge support from John Templeton Foundation, NSF DMR-1207469 and ONR N00014-13-1-0301.

  14. An inhomogeneous Josephson phase in thin-film and high- Tc superconductors

    NASA Astrophysics Data System (ADS)

    Imry, Y.; Strongin, M.; Homes, C. C.

    2008-02-01

    In many cases inhomogeneities are known to exist near the metal (or superconductor)-insulator transition, as follows from well-known domain-wall arguments. If the conducting regions are large enough (i.e. when the T = 0 superconducting gap is much larger than the single-electron level spacing), and if they have superconducting correlations, it becomes energetically favorable for the system to go into a Josephson-coupled zero-resistance state before (i.e. at higher resistance than) becoming a “real” metal. We show that this is plausible by a simple comparison of the relevant coupling constants. For small grains in the above sense, the electronic grain structure is washed out by delocalization and thus becomes irrelevant. When the proposed “Josephson state” is quenched by a magnetic field, an insulating, rather than a metallic, state should appear. This has been shown [J. Tu, M. Strongin, Y. Imry, cond-mat/0405625 (2004)] to be consistent with the existing data on oxide materials as well as ultra-thin-films. We discuss the Uemura correlations versus Homes’ law, and derive the former for the large-grain Josephson array (inhomogenous superconductor) model. The small-grain case behaves like a dirty homogenous metal. It should obey Homes’ law provided that the system is in the dirty supeconductivity limit. A speculation as to why that is typically the case for d-wave superconductors is presented.

  15. Thin film processing and characterization of high-temperature superconductors; Proceedings of the Topical Conference, Anaheim, CA, Nov. 6, 1987

    Microsoft Academic Search

    James M. E. Harper; Richard J. Colton; Leonard C. Feldman

    1988-01-01

    Techniques for preparing, treating, and characterizing thin films of high-Tc superconductors are examined in reviews and reports of recent investigations. Topics addressed include evaporation, sputtering, substrate effects, laser ablation, spin-on\\/pyrolysis, plasma-spray deposition, electron spectroscopy, and surface and interface chemistry. Consideration is given to negative-ion effects during magnetron and ion-beam sputtering of YBa2Cu3O(x), critical current and texture relationships in YBa2Cu3O7 thin

  16. Fabrication of high T(sub c) superconductor thin film devices: Center director's discretionary fund

    NASA Astrophysics Data System (ADS)

    Sisk, R. C.

    1992-08-01

    This report describes a technique for fabricating superconducting weak link devices with micron-sized geometries etched in laser ablated Y1Ba2Cu3O(x) (YBCO) thin films. Careful placement of the weak link over naturally occurring grain boundaries exhibited in some YBCO thin films produces Superconducting Quantum Interference Devices (SQUID's) operating at 77 K.

  17. Effect of ferromagnetic film thickness on magnetoresistance of thin-film superconductor-ferromagnet hybrids

    NASA Astrophysics Data System (ADS)

    Aladyshkin, A. Yu.; Volodin, A. P.; Moshchalkov, V. V.

    2010-08-01

    We study the influence of the thickness Df of the plain ferromagnetic (F) film on the electrical resistance of the flux-coupled hybrids, consisting of superconducting (S) Al film and multilayer [Co/Pt] F film with out-of-plain magnetization. The behavior of such hybrids at high and low temperatures is found to be different as follows: the nucleation of superconductivity at high temperatures is governed mainly by the typical lateral dimensions of the magnetic domains, while low-temperature properties are determined by topology of the magnetic template. We show that an increase in the Df value leads to a broadening of the field-intervals and temperature intervals where nonmonotonous dependence of the superconducting critical temperature Tc on the applied magnetic field H is observed (for demagnetized F films). Further increase in the Df value results in a global suppression of superconductivity. Thus, we determined an optimal thickness, when the nonmonotonous dependence Tc(H) can be observed in rather broad T and H range, what can be interesting for further studies of the localized superconductivity in planar Al-based S/F hybrids and for development of the devices which can exploit the localized superconductivity.

  18. Critical behavior of superconductors and electrical transport properties of carbon nanotube thin films

    Microsoft Academic Search

    Hua Xu

    2007-01-01

    With AC microwave measurements from 10 MHz up to 50 GHz and DC nanovolt level measurements we have investigated the superconducting phase transition of YBa2Cu3O7-delta films in zero magnetic field and electrical transport properties of single walled carbon nanotube networks. We studied the microwave conductivity of YBa2Cu3O 7-delta thin films around Tc for different incident microwave power and observed that

  19. Thin film seeds for melt processing textured superconductors for practical applications

    DOEpatents

    Veal, Boyd W. (Downers Grove, IL); Paulikas, Arvydas (Downers Grove, IL); Balachandran, Uthamalingam (Hinsdale, IL); Zhong, Wei (West Lafayette, IN)

    1999-01-01

    A method of fabricating bulk superconducting material such as RBa.sub.2 Cu.sub.3 O.sub.7-.delta. where R is La or Y comprising depositing a thin epitaxially oriented film of Nd or Sm (123) on an oxide substrate. The powder oxides of RBa.sub.2 Cu.sub.3 O.sub.7-.delta. or oxides and/or carbonates of R and Ba and Cu present in mole ratios to form RBa.sub.2 Cu.sub.3 O.sub.7-.delta., where R is Y or La are heated, in physical contact with the thin film of Nd or Sm (123) on the oxide substrate to a temperature sufficient to form a liquid phase in the oxide or carbonate mixture while maintaining the thin film solid to grow a large single domain 123 superconducting material. Then the material is cooled. The thin film is between 200 .ANG. and 2000 .ANG.. A construction prepared by the method is also disclosed.

  20. Thin film seeds for melt processing textured superconductors for practical applications

    DOEpatents

    Veal, B.W.; Paulikas, A.; Balachandran, U.; Zhong, W.

    1999-02-09

    A method of fabricating bulk superconducting material such as RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} where R is La or Y comprising depositing a thin epitaxially oriented film of Nd or Sm (123) on an oxide substrate is disclosed. The powder oxides of RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} or oxides and/or carbonates of R and Ba and Cu present in mole ratios to form RBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}, where R is Y or La are heated, in physical contact with the thin film of Nd or Sm (123) on the oxide substrate to a temperature sufficient to form a liquid phase in the oxide or carbonate mixture while maintaining the thin film solid to grow a large single domain 123 superconducting material. Then the material is cooled. The thin film is between 200 {angstrom} and 2000 {angstrom}. A construction prepared by the method is also disclosed.

  1. Magnetic field dependence of Josephson photoresponse in high-T c superconductor thin films

    NASA Astrophysics Data System (ADS)

    Schneider, Gi.; Huggard, P. G.; O'Brien, T. P.; Blau, W.; Prettl, W.

    1994-02-01

    The Josephson photoresponse of granular high-T c superconductor films to pulsed far infrared laser radiation has been investigated in magnetic fields of up to 3T. Its value is strongly influenced by fields less than 50mT and shows a pronounced hysteresis here. At low bias current densities, jb < 10A/cm 2, an applied field stimulates the photoresponse, while for jb > 100A/cm 2 the photoresponse is depressed. All changes have occured by a field of B < 50mT: for higher fields the photoresponse remains constant. This dependence is interpreted to arise from micrometre sized grain boundary junctions with a strongly inhomogenous critical current distribution on a sub-nanometre scale.

  2. A radio-frequency coil for the microwave characterization of vortex dynamics in thin film superconductors

    NASA Astrophysics Data System (ADS)

    Cuadra-Solís, Pedro-de-Jesús; Fernández-Martínez, Antoni; Hernàndez, Joan Manel; García-Santiago, Antoni; Vanacken, Johan; Moshchalkov, Victor V.

    2015-06-01

    A radio-frequency coil for the experimental investigation of the magnetic properties of thin superconducting films under microwave fields at different values of temperature and dc magnetic field has been developed. The system has been used for low-temperature microwave frequency-dependent magnetization measurements in a Pb thin film with an engineered periodical antidot array. The characteristic frequencies and the electric and magnetic fields of the resonant system formed by a multi-turn coil with a sample loaded in its core are estimated using the helical approach. A good agreement of the calculated values with those recorded in swept-frequency spectra is obtained. The relation between the characteristics of the resonant structure and the frequency-driven magnetic response of the sample at different nominal microwave powers documents the capability and sensitivity of the layout.

  3. A radio-frequency coil for the microwave characterization of vortex dynamics in thin film superconductors.

    PubMed

    Cuadra-Solís, Pedro-de-Jesús; Fernández-Martínez, Antoni; Hernàndez, Joan Manel; García-Santiago, Antoni; Vanacken, Johan; Moshchalkov, Victor V

    2015-06-01

    A radio-frequency coil for the experimental investigation of the magnetic properties of thin superconducting films under microwave fields at different values of temperature and dc magnetic field has been developed. The system has been used for low-temperature microwave frequency-dependent magnetization measurements in a Pb thin film with an engineered periodical antidot array. The characteristic frequencies and the electric and magnetic fields of the resonant system formed by a multi-turn coil with a sample loaded in its core are estimated using the helical approach. A good agreement of the calculated values with those recorded in swept-frequency spectra is obtained. The relation between the characteristics of the resonant structure and the frequency-driven magnetic response of the sample at different nominal microwave powers documents the capability and sensitivity of the layout. PMID:26133852

  4. Infrared and millimeter wave detection using thin films of Pb doped BiSrCaCuO superconductor

    NASA Astrophysics Data System (ADS)

    Phong, L. Ngo

    1995-01-01

    Thin film detectors made of CuO superconductors were developed in our laboratory. This article reports details of the fabrication and testing of Pb doped BiSrCaCuO detectors. The detector comprises a film sensor housed in a small cryostat with built-in bias supply and temperature control circuitry. The film sensor was first deposited by magnetron rf sputtering and then crystallized under a rapid thermal annealing process. The characteristics of the response of the detector under millimeter wave and infrared illumination were investigated. The millimeter wave response exhibited a Josephson component with a D(*) approximately 10(exp 8) - 10(exp 9) cm.Hz(exp (1/2))/W in the wavelength range of 3 - 8 mm. The transient response to short pulses indicated a time constant tau less than or equal to 10 ns for this component. The response to laser pulses was thermal in origin and inherently compressible, preventing saturation of the detector electronics to intense beams. The wide band characteristic of the responses at both infrared and millimeter wavelengths could be confirmed. The damage threshold of the film sensor was shown to exceed 10 mJ / sq cm per 3 ns pulse. The possible use of these detectors for threat detection and the optimization of their figure of merit are discussed.

  5. The use of BaF sub 2 buffer layers for the sputter-deposition of TlCaBaCuO thin-film superconductors

    SciTech Connect

    Hubbard, K.M.; Arendt, P.N.; Brown, D.R.; Cooke, D.W.; Elliott, N.E.; Farr, J.D.; Nastasi, M.; Ott, K.C.; Peterson, E.J.; Reeves, G.A.

    1989-01-01

    Thin films of the Tl-based superconductors often have relatively poor properties because of film/substrate interdiffusion which occurs during the anneal. We have therefore investigated the use of BaF{sub 2} as a diffusion barrier. TlCaBaCuO thin films were deposited by dc magnetron sputtering onto MgO <100> substrates, both with and without an evaporation-deposited BaF{sub 2} buffer layer, and post-annealed in a Tl over-pressure. Electrical properties of the films were determined by four-point probe analysis, and compositions were measured by ion-backscattering spectroscopy. Structural analysis was performed by x-ray diffraction and scanning electron microscopy. The BaF{sub 2} buffer layers were found to significantly improve the properties of the TlCaBaCuO thin films. 8 refs., 3 figs.

  6. Molecular beam deposition of Dy sub 1 Ba sub 2 Cu sub 3 O sub 7 minus. delta. (001) high-temperature superconductor thin films

    SciTech Connect

    Bae, J.; Seshadri, P.; Choudhary, K.M. (University of Notre Dame, Department of Electrical Engineering, Notre Dame, Indiana 46556 (United States))

    1992-03-01

    Epitaxial Dy{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}(001) high-temperature superconductor thin films on LaAlO{sub 3} substrates have been prepared by coevaporation of Dy, BaF{sub 2}, and Cu and postannealing. The vapors in desired ratio were evaporated from effusion cells in a miniature molecular beam deposition system. The films show critical transition temperature ({ital T}{sub {ital c},0}) of 89.5{plus minus}0.5 K. During process development it was found that single phase Dy{sub 1+x}Ba{sub 2{minus}x}Cu{sub 3}O{sub y}(001) thin films can be grown ({ital x}=0 to 0.3). Their electrical properties were useful in calibration of quartz crystal thin film thickness monitor (FTM) for determination of relationships between the actual vapor arrival rate (flux) and FTM reading.

  7. Epitaxial thin films

    DOEpatents

    Hunt, Andrew Tye; Deshpande, Girish; Lin, Wen-Yi; Jan, Tzyy-Jiuan

    2006-04-25

    Epitatial thin films for use as buffer layers for high temperature superconductors, electrolytes in solid oxide fuel cells (SOFC), gas separation membranes or dielectric material in electronic devices, are disclosed. By using CCVD, CACVD or any other suitable deposition process, epitaxial films having pore-free, ideal grain boundaries, and dense structure can be formed. Several different types of materials are disclosed for use as buffer layers in high temperature superconductors. In addition, the use of epitaxial thin films for electrolytes and electrode formation in SOFCs results in densification for pore-free and ideal gain boundary/interface microstructure. Gas separation membranes for the production of oxygen and hydrogen are also disclosed. These semipermeable membranes are formed by high-quality, dense, gas-tight, pinhole free sub-micro scale layers of mixed-conducting oxides on porous ceramic substrates. Epitaxial thin films as dielectric material in capacitors are also taught herein. Capacitors are utilized according to their capacitance values which are dependent on their physical structure and dielectric permittivity. The epitaxial thin films of the current invention form low-loss dielectric layers with extremely high permittivity. This high permittivity allows for the formation of capacitors that can have their capacitance adjusted by applying a DC bias between their electrodes.

  8. Ferromagnetic SrRuO3 thin-film deposition on a spin-triplet superconductor Sr2RuO4 with a highly conducting interface

    NASA Astrophysics Data System (ADS)

    Anwar, M. S.; Shin, Yeong Jae; Lee, Seung Ran; Kang, Sung Jin; Sugimoto, Yuske; Yonezawa, Shingo; Noh, Tae Won; Maeno, Yoshiteru

    2015-01-01

    Ferromagnetic SrRuO3 thin films are deposited on the ab surface of single crystals of the spin-triplet superconductor (TSC) Sr2RuO4 as substrates using pulsed laser deposition. The films are under a severe in-plane compressive strain. Nevertheless, the films exhibit ferromagnetic order with the easy axis along the c-direction below the Curie temperature of 158 K. The electrical transport reveals that the SrRuO3/Sr2RuO4 interface is highly conducting, in contrast with the interface between other normal metals and the ab surface of Sr2RuO4. Our results stimulate investigations on proximity effects between a ferromagnet and a TSC.

  9. Mn12-acetate thin film patterns and their interaction with superconductors

    E-print Network

    Kim, Kyongwan

    2009-05-15

    chemical formula is [Mn12O12(CH3COO)16(H2O)4]#6;2CH3COOH#6;4H2O. As depicted in Fig. II-1, the 8 crystalline complex has a tetragonal lattice, with a = b = 1.7319 nm, c = 1.2388 nm and a crystal lattice belonging to the S4 crystallographic symmetry...-molecule magnet) film. (b) SEM image of the submicron patterns generated by the procedure detailed in (a)?........... 20 III-4 SEM image of the line pattern in Fig.III-3 (b) scanned at higher magnification...

  10. Proximity effects at the interface of a superconductor and a topological insulator in NbN-Bi2Se3 thin film bilayers

    NASA Astrophysics Data System (ADS)

    Koren, Gad

    2015-02-01

    In a search for a simple proximity system of a topological insulator and a superconductor for studying the role of surface versus bulk effects by gating, we report here on a first step toward this goal, namely the choice of such a system and its characterization. We chose to work with thin film bilayers of grainy 5 nm thick NbN films as the superconductor, overlayed with 20 nm thick topological layer of B{{i}2}S{{e}3} and compare the transport results to those obtained on a 5 nm thick reference NbN film on the same wafer. Bilayers with ex situ and in situ prepared NbN-B{{i}2}S{{e}3} interfaces were studied and two kinds of proximity effects were found. At high temperatures just below the superconducting transition, all bilayers showed a conventional proximity effect where the topological B{{i}2}S{{e}3} suppresses the onset or mid-transition Tc of the superconducting NbN films by about 1 K. At low temperatures, a cross-over of the resistance versus temperature curves of the bilayer and reference NbN film occurs, where the bilayers show enhancement of {{T}c}(R=0), Ic (the supercurrent) and the Andreev conductance, as compared to the bare NbN films. This indicates that superconductivity is induced in the B{{i}2}S{{e}3} layer at the interface region in between the NbN grains. Thus an inverse proximity effect in the topological material is demonstrated.

  11. Characterization of the thin-film NbN superconductor for single-photon detection by transport measurements

    NASA Astrophysics Data System (ADS)

    Lin, Shi-Zeng; Ayala-Valenzuela, Oscar; McDonald, Ross D.; Bulaevskii, Lev N.; Holesinger, Terry G.; Ronning, Filip; Weisse-Bernstein, Nina R.; Williamson, Todd L.; Mueller, Alexander H.; Hoffbauer, Mark A.; Rabin, Michael W.; Graf, Matthias J.

    2013-05-01

    The fabrication of high-quality thin superconducting films is essential for single-photon detectors. Their device performance is crucially affected by their material parameters, thus requiring reliable and nondestructive characterization methods after the fabrication and patterning processes. Important material parameters to know are the resistivity, superconducting transition temperature, relaxation time of quasiparticles, and uniformity of patterned wires. In this work, we characterize micropatterned thin NbN films by using transport measurements in magnetic fields. We show that from the instability of vortex motion at high currents in the flux-flow state of the IV characteristic, the inelastic lifetime of quasiparticles can be determined to be about 2 ns. Additionally, from the depinning transition of vortices at low currents, as a function of magnetic field, the size distribution of grains can be extracted. This size distribution is found to be in agreement with the film morphology obtained from scanning electron microscopy and high-resolution transmission electron microscopy images.

  12. Pyrolyzed thin film carbon

    NASA Technical Reports Server (NTRS)

    Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Harder, Theodore (Inventor); Konishi, Satoshi (Inventor); Miserendino, Scott (Inventor)

    2010-01-01

    A method of making carbon thin films comprises depositing a catalyst on a substrate, depositing a hydrocarbon in contact with the catalyst and pyrolyzing the hydrocarbon. A method of controlling a carbon thin film density comprises etching a cavity into a substrate, depositing a hydrocarbon into the cavity, and pyrolyzing the hydrocarbon while in the cavity to form a carbon thin film. Controlling a carbon thin film density is achieved by changing the volume of the cavity. Methods of making carbon containing patterned structures are also provided. Carbon thin films and carbon containing patterned structures can be used in NEMS, MEMS, liquid chromatography, and sensor devices.

  13. Computer-controlled ion beam deposition systems for high Tc superconductor and other multi-component oxide thin films and layered structures

    Microsoft Academic Search

    A. R. Krauss; Dieter M. Gruen; O. Auciello; A. I. Kingon; M. S. Ameen; T. M. Graettinger; C. S. Rou; C. S. Soble; Y. L. Liu; T. Barr

    1990-01-01

    A single beam, multiple target (SBMT) deposition system which features a rotating target holder with either elemental or simple compound targets has been developed for the production of layered thin film structures and multicomponent oxide, silicide or other compound thin films. We are employing the SBMT ion beam sputtering system for the deposition of high temperature superconducting films and electro-optical

  14. Formation of thin film Tl-based high-Tc? superconducting oxides from amorphous alloy precursors

    E-print Network

    Williams, John Charles

    1991-01-01

    . Magnetoresistance 3. Jc Measurement for Film BF01890. 4. Resistivity and Hall Effect Measurements IV. CONCLUSION REFERENCES. . VITA LIST OF TABLES 1. 1 Tl-based Superconductor Metal Ion Stacking Sequences. . . . 3. 1 Alloy Pellets. 3. 2 Film Production.... Fundamental Properties. 2. Perovskite Crystal Structure. 3. Perovskite Crystal Structure Modifications 4, Structure of Thallate Superconductors . . B. Thallium-based Thin Film Superconductors. . . . 1. Tl-based Thin Film Production Methods. . . . 2...

  15. Sputtered thin magnetic films

    Microsoft Academic Search

    W. Mayer

    1966-01-01

    Sputtered magnetic thin films have been studied for the purpose of evaluating both the deposition technique and the films fabricated by this technique. Results of these studies show the sputtering process to be relatively simple to control and the films to be highly uniform and reproducible. Some indications of correlation between crystalline structure and the magnetic properties of the films

  16. Absence of a proximity effect for a thin-films of a Bi2Se3 topological insulator grown on top of a Bi2Sr2CaCu2O(8+?) cuprate superconductor.

    PubMed

    Yilmaz, T; Pletikosi?, I; Weber, A P; Sadowski, J T; Gu, G D; Caruso, A N; Sinkovic, B; Valla, T

    2014-08-01

    Proximity-induced superconductivity in a 3D topological insulator represents a new avenue for observing zero-energy Majorana fermions inside vortex cores. Relatively small gaps and low transition temperatures of conventional s-wave superconductors put hard constraints on these experiments. Significantly larger gaps and higher transition temperatures in cuprate superconductors might be an attractive alternative to considerably relax these constraints, but it is not clear whether the proximity effect would be effective in heterostructures involving cuprates and topological insulators. Here, we present angle-resolved photoemission studies of thin Bi(2)Se(3) films grown in situ on optimally doped Bi(2)Sr(2)CaCu(2)O(8+?) substrates that show the absence of proximity-induced gaps on the surfaces of Bi(2)Se(3) films as thin as a 1.5 quintuple layer. These results suggest that the superconducting proximity effect between a cuprate superconductor and a topological insulator is strongly suppressed, likely due to a very short coherence length along the c axis, incompatible crystal and pairing symmetries at the interface, small size of the topological surface state's Fermi surface, and adverse effects of a strong spin-orbit coupling in the topological material. PMID:25148345

  17. Quasiparticle generation efficiency in superconducting thin films

    NASA Astrophysics Data System (ADS)

    Guruswamy, T.; Goldie, D. J.; Withington, S.

    2014-05-01

    Thin-film superconductors with thickness ˜30-500 nm are used as non-equilibrium quantum detectors for photons, phonons or more exotic particles. One of the most basic questions in determining their limiting sensitivity is the efficiency with which the quanta of interest couple to the detected quasiparticles. As low temperature superconducting resonators, thin films are attractive candidates for producing quantum-sensitive arrayable sensors and the readout uses an additional microwave probe. We have calculated the quasiparticle generation efficiency ?s for low energy photons in a representative, clean thin-film superconductor (Al) operating well below its superconducting transition temperature as a function of film thickness, within the framework of the coupled kinetic equations described by Chang and Scalapino (1978 J. Low Temp. Phys. 31 1-32). We have also included the effect of a lower frequency probe. We show that phonon loss from the thin film reduces ?s by as much as 40% compared to earlier models that considered relatively thick films or infinite volumes. We also show that the presence of the probe and signal enhances the generation efficiency slightly. We conclude that the ultimate limiting noise equivalent power of this class of detector is determined by the thin-film geometry.

  18. Thin Films Module

    NSDL National Science Digital Library

    This page from Nano-Link contains the document required for the thin films module. The activity requires a background in eight grade science. This 9 page guide includes background information on thin film interference, a hands-on learning activity, links to multimedia resources, and further readings. Visitors must complete a quick and free registration to access the materials.

  19. Carbon thin film thermometry

    NASA Technical Reports Server (NTRS)

    Collier, R. S.; Sparks, L. L.; Strobridge, T. R.

    1973-01-01

    The work concerning carbon thin film thermometry is reported. Optimum film deposition parameters were sought on an empirical basis for maximum stability of the films. One hundred films were fabricated for use at the Marshall Space Flight Center; 10 of these films were given a precise quasi-continuous calibration of temperature vs. resistance with 22 intervals between 5 and 80 K using primary platinum and germanium thermometers. Sensitivity curves were established and the remaining 90 films were given a three point calibration and fitted to the established sensitivity curves. Hydrogen gas-liquid discrimination set points are given for each film.

  20. Studies of Solution Deposited Cerium Oxide Thin Films on Textured Ni-Alloy Substractes for YBCO Superconductor

    SciTech Connect

    Stewart, Erin L [ORNL; Bhuiyan, Md S [ORNL; Sathyamurthy, Srivatsan [ORNL; Paranthaman, Mariappan Parans [ORNL

    2006-01-01

    Cerium oxide (CeO2) buffer layers play an important role for the development of YBa2Cu3O7-x (YBCO) based superconducting tapes using the rolling assisted biaxially textured substrates (RABiTS) approach. The chemical solution deposition (CSD) approach has been used to grow epitaxial CeO2 films on textured Ni-3 a 4% W alloy substrates with various starting precursors of ceria. Precursors such as cerium acetate, cerium acetylacetonate, cerium 2-ethylhexanoate, cerium nitrate, and cerium trifluoroacetate were prepared in suitable solvents. The optimum growth conditions for these cerium precursors were Ar-4% H2 gas processing atmosphere, solution concentration levels of 0.2-0.5 M, a dwell time of 15 min, and a process temperature range of 1050-1150 degrees C. X-ray diffraction, AFM, SEM, and optical microscopy were used to characterize the CeO2 films. Highly textured CeO2 layers were obtained on Ni-W substrates with both cerium acetate and cerium acetylacetonate as starting precursors. YBCO films with a Jc of 1.5 MA/cm2 were obtained on cerium acetylacetonate-based CeO2 films with sputtered YSZ and CeO2 cap layers.

  1. Studies of solution deposited cerium oxide thin films on textured Ni-alloy substrates for YBCO superconductor

    SciTech Connect

    Stewart, E. [Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6100 (United States); Bhuiyan, M.S. [Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6100 (United States); Sathyamurthy, S. [Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6100 (United States); Paranthaman, M. [Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6100 (United States)]. E-mail: paranthamanm@ornl.gov

    2006-06-15

    Cerium oxide (CeO{sub 2}) buffer layers play an important role for the development of YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) based superconducting tapes using the rolling assisted biaxially textured substrates (RABiTS) approach. The chemical solution deposition (CSD) approach has been used to grow epitaxial CeO{sub 2} films on textured Ni-3 at.% W alloy substrates with various starting precursors of ceria. Precursors such as cerium acetate, cerium acetylacetonate, cerium 2-ethylhexanoate, cerium nitrate, and cerium trifluoroacetate were prepared in suitable solvents. The optimum growth conditions for these cerium precursors were Ar-4% H{sub 2} gas processing atmosphere, solution concentration levels of 0.2-0.5 M, a dwell time of 15 min, and a process temperature range of 1050-1150 deg. C. X-ray diffraction, AFM, SEM, and optical microscopy were used to characterize the CeO{sub 2} films. Highly textured CeO{sub 2} layers were obtained on Ni-W substrates with both cerium acetate and cerium acetylacetonate as starting precursors. YBCO films with a J {sub c} of 1.5 MA/cm{sup 2} were obtained on cerium acetylacetonate-based CeO{sub 2} films with sputtered YSZ and CeO{sub 2} cap layers.

  2. Thin Film Growth

    NSDL National Science Digital Library

    Rack, Philip D.

    This is a PDF version of lecture slides that discuss thin film growth processes. Slide topics include plasma properties, DC glow discharge, ionization, plasma species, magnetrons, collisions, and chemical reactions. Numerous charts and mathematical formulas are presented.

  3. Protein Thin Film Machines

    E-print Network

    Federici, Stefania

    We report the first example of microcantilever beams that are reversibly driven by protein thin film machines fuelled by cycling the salt concentration of the surrounding solution. We also show that upon the same salinity ...

  4. Electroluminescence in thin films

    Microsoft Academic Search

    Reiner H. Mauch

    1996-01-01

    The three most important technologies for future display applications where electroluminescence (EL) in thin films is used for light generation are discussed. These technologies are firstly, Alq- and PPV-based organic light emitting diodes (LED); secondly, inorganic a-SiC LED and thirdly, ac-driven thin film electroluminescent devices based on II–VI compounds. The last of these is of the high-field EL-type whereas the

  5. Defects in Thin Films

    SciTech Connect

    Martin, Peter M.

    2004-01-01

    Defects have been the bane of, and led to the failure of many a thin film. Defects come in many shapes, forms and sizes, and are a fact of life in the coating business. Virtually every technology and product related to thin film materials has had to deal with these little menaces. Defects include voids, uncompensated bonds, cracks, nodules, particulates, bubbles, inclusions, pin holes, and chemical defects such as impurities and chemisorbed materials.

  6. Simulated Thin-Film Growth and Imaging

    NASA Astrophysics Data System (ADS)

    Schillaci, Michael

    2001-06-01

    Thin-films have become the cornerstone of the electronics, telecommunications, and broadband markets. A list of potential products includes: computer boards and chips, satellites, cell phones, fuel cells, superconductors, flat panel displays, optical waveguides, building and automotive windows, food and beverage plastic containers, metal foils, pipe plating, vision ware, manufacturing equipment and turbine engines. For all of these reasons a basic understanding of the physical processes involved in both growing and imaging thin-films can provide a wonderful research project for advanced undergraduate and first-year graduate students. After producing rudimentary two- and three-dimensional thin-film models incorporating ballsitic deposition and nearest neighbor Coulomb-type interactions, the QM tunneling equations are used to produce simulated scanning tunneling microscope (SSTM) images of the films. A discussion of computational platforms, languages, and software packages that may be used to accomplish similar results is also given.

  7. Magnetite thin films

    Microsoft Academic Search

    J. Feng; C. Bajorek; M.-A. Nicolet

    1972-01-01

    A low temperature process for converting hematite (?-Fe2O3) thin films into magnetite (Fe3O4is described. The films produced are unambiguously identified as magnetite by several complementary methods of analysis. These include ?-backscattering spectrography, X-ray powder diffractometry, and observations of electrical, magnetic, and optical properties.

  8. Electric breakdown effect in the current-voltage characteristics of amorphous indium oxide thin films near the superconductor-insulator transition

    Microsoft Academic Search

    O. Cohen; M. Ovadia; D. Shahar

    2011-01-01

    Current-voltage characteristics in the insulator bordering superconductivity in disordered thin films exhibit current jumps of several orders of magnitude due to the development of a thermally bistable electronic state at very low temperatures. In this high-resolution study we find that the jumps can be composed of many (up to 100) smaller jumps that appear to be random. This indicates that

  9. High performance superconducting thin films on large area substrates

    NASA Astrophysics Data System (ADS)

    Lauder, A.; Wilker, C.; Kountz, D. J.; Holstein, W. L.; Face, D. W.

    1993-03-01

    The first fabrication of 3-in-diameter, thin films of thallium-based superconductors is reported. (Tl0.5Pb0.5)Sr2Ca2Cu3O9 thin films on LaAlO3 are found to display the best surface resistance (Rs) properties of any superconductor at higher temperatures and show approximately 50x better performance than copper at 100 K and 10 GHz. A Tl2Ba2CaCu2O8 thin film, processed as a 1.8-m-long, 10-micron-wide meander line carries about 1 x 10 exp 7 A/sq cm at 4.2 K and 2 x 10 exp 6 A/sq cm at 80 K. The thallium-based superconductors are compared to YBa2Cu3O7 with respect to Tc, Rs, and Q.

  10. Thin film solar cell workshop

    NASA Technical Reports Server (NTRS)

    Armstrong, Joe; Jeffrey, Frank

    1993-01-01

    A summation of responses to questions posed to the thin-film solar cell workshop and the ensuing discussion is provided. Participants in the workshop included photovoltaic manufacturers (both thin film and crystalline), cell performance investigators, and consumers.

  11. NMR characterization of thin films

    DOEpatents

    Gerald, II, Rex E. (Brookfield, IL); Klingler, Robert J. (Glenview, IL); Rathke, Jerome W. (Homer Glen, IL); Diaz, Rocio (Chicago, IL); Vukovic, Lela (Westchester, IL)

    2008-11-25

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  12. Black thin film silicon

    Microsoft Academic Search

    Svetoslav Koynov; Martin S. Brandt; Martin Stutzmann

    2011-01-01

    ``Black etching'' has been proposed previously as a method for the nanoscale texturing of silicon surfaces, which results in an almost complete suppression of reflectivity in the spectral range of absorption relevant for photovoltaics. The method modifies the topmost 150 to 300 nm of the material and thus also is applicable for thin films of silicon. The present work is

  13. Electrochromic thin films

    Microsoft Academic Search

    C. Nyman; U. Gullenberg; M. Leppihalme

    1987-01-01

    An electrochromic material has the property of changing color when voltage is applied across it. It is possible electronically to alter a window's transmission and reflection properties by use of electrochromic thin films. This allows regulation of conductive and radiative heat transfer rates, with variable optical attenuation in the visible and infrared part of the solar radiation. Suitable materials for

  14. Black thin film silicon

    NASA Astrophysics Data System (ADS)

    Koynov, Svetoslav; Brandt, Martin S.; Stutzmann, Martin

    2011-08-01

    "Black etching" has been proposed previously as a method for the nanoscale texturing of silicon surfaces, which results in an almost complete suppression of reflectivity in the spectral range of absorption relevant for photovoltaics. The method modifies the topmost 150 to 300 nm of the material and thus also is applicable for thin films of silicon. The present work is focused on the optical effects induced by the black-etching treatment on hydrogenated amorphous and microcrystalline silicon thin films, in particular with respect to their application in solar cells. In addition to a strong reduction of the reflectivity, efficient light trapping within the modified thin films is found. The enhancement of the optical absorption due to the light trapping is investigated via photometric measurements and photothermal deflection spectroscopy. The correlation of the texture morphology (characterized via atomic force microscopy) with the optical effects is discussed in terms of an effective medium with gradually varying optical density and in the framework of the theory of statistical light trapping. Photoconductivity spectra directly show that the light trapping causes a significant prolongation of the light path within the black silicon films by up to 15 ?m for ˜1 ?m thick films, leading to a significant increase of the absorption in the red.

  15. Thin-film photovoltaics

    NASA Astrophysics Data System (ADS)

    Dhere, Neelkanth G.; Dhere, Ramesh G.

    2005-07-01

    CdTe and CuIn1-xGaxSe2-ySy (CIGSS) are ideal candidates for thin-film solar cells. Present photovoltaic (PV) conversion efficiencies of champion thin-film solar cells are: CuIn1-xGaxSe2 (CIGS) 19.5%, CdTe 16.5%, and a-Si:H 12.4%. Thin-film PV modules could spearhead production growth of photovoltaics in the United States because of their added production capacity. For this purpose, module efficiencies must be improved to the 13%-15% range. Obtaining Ohmic contacts is difficult, especially for CdTe, because of the inherently low p-type doping level. Therefore, increasing the p-type doping level is important. Growth of CIGSS film must be controlled carefully as it transitions from Cu-rich to In-rich composition. Other issues for CIGSS cells are minimizing indium consumption, and increasing process throughput of selenization/sulfurization and transparent conducting oxide deposition. Development of all-dry processing for CdS deposition would be beneficial for both cells. This paper discusses basic devices and related issues.

  16. Multilayer Thin Films for SRF Accelerating Cavities

    NASA Astrophysics Data System (ADS)

    Bowring, Daniel Leo

    2011-12-01

    Multilayer films on the interior of a superconducting radio frequency (SRF) accelerating cavity have the potential to increase the lower critical magnetic field Hc1 of the bulk cavity material [A. Gurevich, Appl. Phys. Lett. 88, 012511 (2006)]. A cavity with enhanced Hc1 can tolerate higher accelerating gradients, allowing for the construction of SRF particle accelerators with lower capital costs, and more stable beams and cryogenic systems. Multilayer films are composed of alternating layers of insulator and superconductor, each of which layer is thinner than the Loudon penetration depth of the superconductor. This dissertation presents an experimental program for the evaluation of multilayer thin films for SRF, as well as the first evaluation of such films in the RF regime. A stripline disk resonator operating at 2.8 GHz supplies field to a small, flat multilayer sample, in which the superconducting film is (Nb, Ti)N and the insulating film is Al 2O3. By measuring the Q of the resonator, Hc1 may be measured and compared with equivalent bulk superconducting samples.

  17. Advanced thin film thermocouples

    NASA Technical Reports Server (NTRS)

    Kreider, K. G.; Semancik, S.; Olson, C.

    1984-01-01

    The fabrication, materials characterization, and performance of thin film platinum rhodium thermocouples on gas turbine alloys was investigated. The materials chosen for the study were the turbine blade alloy systems MAR M200+Hf with NiCoCrAlY and FeCrAlY coatings, and vane alloy systems MAR M509 with FeCrAlY. Research was focussed on making improvements in the problem areas of coating substrate stability, adhesion, and insulation reliability and durability. Diffusion profiles between the substrate and coating with and without barrier coatings of Al2O3 are reported. The relationships between fabrication parameters of thermal oxidation and sputtering of the insulator and its characterization and performance are described. The best thin film thermocouples were fabricated with the NiCoCrAlY coatings which were thermally oxidized and sputter coated with Al2O3.

  18. Diplomarbeit in Organic Thin Films

    E-print Network

    Schreiber, Frank

    with an ultra-high vacuum chamber · In situ preparation and characterization of organic thin films Low EnergyDiplomarbeit in Organic Thin Films 2013 Title: Thermal Desorption Spectroscopy of Organic Thin varies strongly for different molecules and metal substrates. Thermal Desorption Spectroscopy (TDS) can

  19. Enhanced Superconducting Properties of Iron Chalcogenide Thin Films

    E-print Network

    Chen, Li

    2013-07-26

    . Compared with its bulk counterpart, iron-based superconductor thin film has a great potential in developing the ordered quasi-2D structure and is suitable for coating technology which has already been applied in YBa_2Cu_3 O_7-x coated conductors...

  20. Superconducting thin films. (Latest citations from the EI Compendex*plus database). Published Search

    SciTech Connect

    NONE

    1997-12-01

    The bibliography contains citations concerning the design, fabrication, structures, and properties of superconducting thin films used in microelectronics and optoelectronics. References discuss high temperature superconductors, oxide superconductors, superconducting transition temperatures, critical current density, yttrium barium copper oxide thin films, and yttrium stabilized substrates. Superconducting devices, filters, resonators, and circuits are also reviewed. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  1. Magnetic flux penetration into superconducting thin films.

    NASA Technical Reports Server (NTRS)

    Peabody, G. E.; Meservey, R.

    1972-01-01

    The quantum-interference technique developed by Meservey (1965) is used to measure directly the absolute value of the penetration depth in lead in tin superconducting thin films. The technique assumes that the change in phase of the superconducting wave function around any contour within the superconductor must be 2 pi n, where n is a nonnegative integer. Results show that the critical current of a superconducting interferometer with two parallel junctions is not strictly periodic in the applied magnetic flux with a period equal to the flux quantum because of the magnetic field dependence of the critical currents of the junctions.

  2. Nonlinear optical thin films

    NASA Technical Reports Server (NTRS)

    Leslie, Thomas M.

    1993-01-01

    A focused approach to development and evaluation of organic polymer films for use in optoelectronics is presented. The issues and challenges that are addressed include: (1) material synthesis, purification, and the tailoring of the material properties; (2) deposition of uniform thin films by a variety of methods; (3) characterization of material physical properties (thermal, electrical, optical, and electro-optical); and (4) device fabrication and testing. Photonic materials, devices, and systems were identified as critical technology areas by the Department of Commerce and the Department of Defense. This approach offers strong integration of basic material issues through engineering applications by the development of materials that can be exploited as the active unit in a variety of polymeric thin film devices. Improved materials were developed with unprecedented purity and stability. The absorptive properties can be tailored and controlled to provide significant improvement in propagation losses and nonlinear performance. Furthermore, the materials were incorporated into polymers that are highly compatible with fabrication and patterning processes for integrated optical devices and circuits. By simultaneously addressing the issues of materials development and characterization, keeping device design and fabrication in mind, many obstacles were overcome for implementation of these polymeric materials and devices into systems. We intend to considerably improve the upper use temperature, poling stability, and compatibility with silicon based devices. The principal device application that was targeted is a linear electro-optic modulation etalon. Organic polymers need to be properly designed and coupled with existing integrated circuit technology to create new photonic devices for optical communication, image processing, other laser applications such as harmonic generation, and eventually optical computing. The progression from microscopic sample to a suitable film-forming material in a working device is a complex, multifaceted endeavor. It requires close attention to maintaining the optical properties of the electro-optic active portion of the polymer while manipulating the polymer structure to obtain the desired secondary polymer properties.

  3. Flux penetration in patterned superconducting thin films with multiply connected geometry

    E-print Network

    Wijngaarden, Rinke J.

    Flux penetration in patterned superconducting thin films with multiply connected geometry K.A. L study flux penetration in superconducting thin films. The sam- ples are patterned in the shape that the flux penetration in real superconductors does not show the behavior predicted recently by Chandran

  4. Magnetic penetration depth measurements of superconducting thin films by a microstrip resonator technique

    E-print Network

    Anlage, Steven

    Magnetic penetration depth measurements of superconducting thin films by a microstrip resonator dependence of the magnetic penetration depth, n(T), in superconducting thin films. Because the method relies-lying pair breaking excitations of the superconductor. Absolute penetration depth values can also be obtained

  5. Thin films: Past, present, future

    SciTech Connect

    Zweibel, K.

    1995-04-01

    This report describes the characteristics of the thin film photovoltaic modules necessary for an acceptable rate of return for rural areas and underdeveloped countries. The topics of the paper include a development of goals of cost and performance for an acceptable PV system, a review of current technologies for meeting these goals, issues and opportunities in thin film technologies.

  6. INTERFERENCE Interference from Thin Films

    E-print Network

    La Rosa, Andres H.

    INTERFERENCE Interference from Thin Films Lecture notes La Rosa Portland State University PH-213 #12;#12;Reflection and transmission at an air- glass interface The effects of interference can be best through, a sheet of glass #12;Out of phase #12;In phase #12;#12;Interference from thin films Key reasoning

  7. Thin film ion conducting coating

    DOEpatents

    Goldner, Ronald B. (Lexington, MA); Haas, Terry (Sudbury, MA); Wong, Kwok-Keung (Watertown, MA); Seward, George (Arlington, MA)

    1989-01-01

    Durable thin film ion conducting coatings are formed on a transparent glass substrate by the controlled deposition of the mixed oxides of lithium:tantalum or lithium:niobium. The coatings provide durable ion transport sources for thin film solid state storage batteries and electrochromic energy conservation devices.

  8. Thin film concentrator panel development

    Microsoft Academic Search

    D. K. Zimmerman

    1982-01-01

    The development and testing of a rigid panel concept that utilizes a thin film reflective surface for application to a low-cost point-focusing solar concentrator is discussed. It is shown that a thin film reflective surface is acceptable for use on solar concentrators, including 1500 F applications. Additionally, it is shown that a formed steel sheet substrate is a good choice

  9. Polyimide Aerogel Thin Films

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann; Guo, Haiquan

    2012-01-01

    Polyimide aerogels have been crosslinked through multifunctional amines. This invention builds on "Polyimide Aerogels With Three-Dimensional Cross-Linked Structure," and may be considered as a continuation of that invention, which results in a polyimide aerogel with a flexible, formable form. Gels formed from polyamic acid solutions, end-capped with anhydrides, and cross-linked with the multifunctional amines, are chemically imidized and dried using supercritical CO2 extraction to give aerogels having density around 0.1 to 0.3 g/cubic cm. The aerogels are 80 to 95% porous, and have high surface areas (200 to 600 sq m/g) and low thermal conductivity (as low as 14 mW/m-K at room temperature). Notably, the cross-linked polyimide aerogels have higher modulus than polymer-reinforced silica aerogels of similar density, and can be fabricated as both monoliths and thin films.

  10. Ferromagnetic thin films

    DOEpatents

    Krishnan, Kannan M. (Berkeley, CA)

    1994-01-01

    A ferromagnetic .delta.-Mn.sub.1-x Ga.sub.x thin film having perpendicular anisotropy is described which comprises: (a) a GaAs substrate, (b) a layer of undoped GaAs overlying said substrate and bonded thereto having a thickness ranging from about 50 to about 100 nanometers, (c) a layer of .delta.-Mn.sub.1-x Ga.sub.x overlying said layer of undoped GaAs and bonded thereto having a thickness ranging from about 20 to about 30 nanometers, and (d) a layer of GaAs overlying said layer of .delta.-Mn.sub.1-x Ga.sub.x and bonded thereto having a thickness ranging from about 2 to about 5 nanometers, wherein x is 0.4 .+-.0.05.

  11. Ferromagnetic thin films

    DOEpatents

    Krishnan, K.M.

    1994-12-20

    A ferromagnetic [delta]-Mn[sub 1[minus]x]Ga[sub x] thin film having perpendicular anisotropy is described which comprises: (a) a GaAs substrate, (b) a layer of undoped GaAs overlying said substrate and bonded thereto having a thickness ranging from about 50 to about 100 nanometers, (c) a layer of [delta]-Mn[sub 1[minus]x]Ga[sub x] overlying said layer of undoped GaAs and bonded thereto having a thickness ranging from about 20 to about 30 nanometers, and (d) a layer of GaAs overlying said layer of [delta]-Mn[sub 1[minus]x]Ga[sub x] and bonded thereto having a thickness ranging from about 2 to about 5 nanometers, wherein x is 0.4[+-]0.05. 7 figures.

  12. Thin-film structures for photovoltaics

    SciTech Connect

    Jones, E.D. [ed.] [Sandia National Labs., Albuquerque, NM (United States); Kalejs, J. [ed.] [ASE Americas Inc., Billerica, MA (United States); Noufi, R.; Sopori, B. [eds.] [National Renewable Energy Lab., Golden, CO (United States)

    1998-12-31

    These proceedings contain 48 papers arranged under the following topical sections: Silicon-based thin films (18 papers); Group II-VI-based thin films (17 papers); Group III-V-based thin films (5 papers); and Thin films--General (9 papers). Papers have been processed separately for inclusion on the data base.

  13. Thin film passive ring resonator laser gyro

    Microsoft Academic Search

    J. P. Segre; J. R. Haavisto

    1987-01-01

    This patent describes a thin film laser gyro comprising: a solid state laser; a thin film passive ring resonator; a thin film delivery loop waveguide means evanescently coupled to the resonator to deliver light from the laser into the resonator; a thin film electro-optic switch means to alternatingly inject a clockwise and a counterclockwise beam of light from the laser

  14. Thin film cell development workshop report

    NASA Technical Reports Server (NTRS)

    Woodyard, James R.

    1991-01-01

    The Thin Film Development Workshop provided an opportunity for those interested in space applications of thin film cells to debate several topics. The unique characteristics of thin film cells as well as a number of other issues were covered during the discussions. The potential of thin film cells, key research and development issues, manufacturing issues, radiation damage, substrates, and space qualification of thin film cells were discussed.

  15. System for depositing thin films

    NASA Technical Reports Server (NTRS)

    Tashbar, P. W. (inventor)

    1974-01-01

    A system for depositing a thin film of one material on another is described. A mass filter is interposed between the source of material being deposited and the object upon which deposition is being made.

  16. Surfactant instabilities on thin films

    E-print Network

    Aessopos, Angelica

    2005-01-01

    The deposition of a surfactant drop over a thin liquid film may be accompanied by a fingering instability. In this work, we present experimental results which identify the critical parameters that govern the shape and ...

  17. Resistivity of Permalloy thin films

    Microsoft Academic Search

    A. F. Mayadas; J. F. Janak; A. Gangulee

    1974-01-01

    Data on resistivity at room temperature in polycrystalline and single-crystal Permalloy (80 Ni-20 Fe) thin films are analyzed in terms of grain boundary scattering and the dc size effect, respectively.

  18. Thin-film temperature sensor.

    NASA Technical Reports Server (NTRS)

    Maserjian, J.

    1972-01-01

    A new device has been developed for sensing small and rapid temperature changes accompanying biochemical reactions. The active element consists of an evaporated thin-film capacitor having a relatively strong temperature dependence. This dependence is derived from electron trapping effects in the thin amorphous dielectric film. A voltage output of at least 50 mV/deg can be obtained prior to amplification by using a resonant ac bridge circuit operating at 100 kHz. The corresponding noise output for a 10 kHz bandwidth can with an optimum circuit be as low as 4 microvolts. Therefore, the minimum detectable temperature change would be 80 microdegrees at 10 kHz. Rapid thermal response is assured by supporting the thin-film capacitor on a thin anodic tantalum oxide film suspended across an electrolytically etched window in a tantalum foil.

  19. Vertically Aligned Nanocomposite Thin Films

    E-print Network

    Bi, Zhenxing

    2012-07-16

    and epitaxial growth ability on given substrates. In the present work, we investigated unique epitaxial two-phase VAN (BiFeO 3)x:(Sm2O 3)1-x and (La0.7Sr0.3MnO 3)x:(Mn3 O 4)1-x thin film systems by pulsed laser deposition. These VAN thin films exhibit a highly...

  20. Vertically Aligned Nanocomposite Thin Films 

    E-print Network

    Bi, Zhenxing

    2012-07-16

    and epitaxial growth ability on given substrates. In the present work, we investigated unique epitaxial two-phase VAN (BiFeO3)x:(Sm2O3)1-x and (La0.7Sr0.3MnO3)x:(Mn3O4)1-x thin film systems by pulsed laser deposition. These VAN thin films exhibit a highly...

  1. Multilayer Thin-Film Microcapacitors

    NASA Technical Reports Server (NTRS)

    Thakoor, Sarita; Thakoor, Anil; Karmon, Dan

    1995-01-01

    Miniature capacitors containing multiple alternating thin-film dielectric and metal layers proposed, especially for use in integrated and hybrid electronic circuits. Because capacitance inversely proportional to thickness of dielectric layers, use of thin, high-quality dielectric layers affords capacitance and energy-storage densities much greater than now available. These devices much smaller and more reliable than state-of-art capacitors.

  2. thin film capacitors

    NASA Astrophysics Data System (ADS)

    Bodeux, Romain; Gervais, Monique; Wolfman, Jérôme; Gervais, François

    2014-09-01

    CaCu3Ti4O12 (CCTO) thin films were grown by pulsed laser deposition on Pt and La0.9Sr1.1NiO4 (LSNO) bottom electrodes. The electrical characteristics of the CCTO/Pt and CCTO/LSNO Schottky junctions have been analyzed by impedance spectroscopy, capacitance-voltage (C-V) and current-voltage (I-V) measurements as a function of frequency (40 Hz-1 MHz) and temperature (300-475 K). Similar results were obtained for the two Schottky diodes. The conduction mechanism through the Schottky junctions was described using a thermionic emission model and the electrical parameters were determined. The strong deviation from the ideal I-V characteristics and the increase in capacitance at low frequency for -0.5 V bias are in agreement with the presence of traps near the interfaces. Results point toward the important effect of defects generated at the interface by deposition of CCTO.

  3. Photoconductivity of thin organic films

    Microsoft Academic Search

    Nikolai V. Tkachenko; Vladimir Chukharev; Petra Kaplas; Antti Tolkki; Alexander Efimov; Kimmo Haring; Jukka Viheriälä; Tapio Niemi; Helge Lemmetyinen

    2010-01-01

    Thin organic films were deposited on silicon oxide surfaces with golden interdigitated electrodes (interelectrode gap was 2?m), and the film resistivities were measured in dark and under white light illumination. The compounds selected for the measurements include molecules widely used in solar cell applications, such as polythiophene (PHT), fullerene (C60), pyrelene tetracarboxylic diimide (PTCDI) and copper phthalocyanine (CuPc), as well

  4. Dewetting of thin polymer films

    Microsoft Academic Search

    Günter Reiter

    1992-01-01

    Thin polystyrene films (<100 nm) on silicon substrates undergo dewetting when annealed above the glass transition temperature. Three different stages can be distinguished: The smooth films break up by the creation of cylindrical holes. The holes then grow and form rims ahead of them which finally contact each other creating ``cellular'' structures. The rims are unstable and decay into droplets.

  5. Stresses in thin film metallization

    Microsoft Academic Search

    Thomas C. Hodge; Sue Ann Bidstrup-Allen; Paul A. Kohl

    1997-01-01

    Stresses in conductors used in microelectronic interconnections are a critical processing and reliability issue. This work examines: 1) the temperature-dependent stress behavior of sputtered and electroplated silver and gold films on silicon substrates; 2) the use of wafer curvature using multiple substrates for the simultaneous determination of coefficient of thermal expansion (CTE) and modulus for thin films. The stress-temperature behavior

  6. Amorphous niobium oxide thin films

    Microsoft Academic Search

    G. Ramírez; S. E. Rodil; S. Muhl; D. Turcio-Ortega; J. J. Olaya; M. Rivera; E. Camps; L. Escobar-Alarcón

    2010-01-01

    Amorphous niobium oxide thin films were deposited by unbalanced reactive magnetron sputtering under different conditions of pressure (2 to 4Pa) and oxygen percentage (9, 17, and 23%). The films were characterized to obtain the relationships between the deposition parameters and the most relevant physical properties (structural, optical, mechanical, surface morphology and optical). The composition was determined by Rutherford backscattering spectroscopy

  7. Vapor deposition of thin films

    DOEpatents

    Smith, David C. (Los Alamos, NM); Pattillo, Stevan G. (Los Alamos, NM); Laia, Jr., Joseph R. (Los Alamos, NM); Sattelberger, Alfred P. (Los Alamos, NM)

    1992-01-01

    A highly pure thin metal film having a nanocrystalline structure and a process of preparing such highly pure thin metal films of, e.g., rhodium, iridium, molybdenum, tungsten, rhenium, platinum, or palladium by plasma assisted chemical vapor deposition of, e.g., rhodium(allyl).sub.3, iridium(allyl).sub.3, molybdenum(allyl).sub.4, tungsten(allyl).sub.4, rhenium(allyl).sub.4, platinum(allyl).sub.2, or palladium(allyl).sub.2 are disclosed. Additionally, a general process of reducing the carbon content of a metallic film prepared from one or more organometallic precursor compounds by plasma assisted chemical vapor deposition is disclosed.

  8. Thin Films for Thermoelectric Applications

    NASA Astrophysics Data System (ADS)

    Silva, M. F.; Ribeiro, J. F.; Carmo, J. P.; Gonçalves, L. M.; Correia, J. H.

    The introduction of nanotechnology opened new horizons previously unattainable by thermoelectric devices. The nano-scale phenomena began to be exploited through techniques of thin-film depositions to increase the efficiency of thermoelectric films. This chapter reviews the fundamentals of the phenomenon of thermoelectricity and its evolution since it was discovered in 1822. This chapter also reviews the thermoelectric devices, the macro to nano devices, describing the most used techniques of physical vapor depositions to deposit thermoelectric thin-films. A custom made deposition chamber for depositing thermoelectric thin films by the thermal co-evaporation technique, where construction issues and specifications are discussed, is then presented. All the steps for obtaining a thermoelectric generator in flexible substrate with the custom deposition chamber (to incorporate in thermoelectric microsystems) are described. The aim of thermoelectric microsystem relays is to introduce an energy harvesting application to power wireless sensor networks (WSN) or biomedical devices. The scanning probe measuring system for characterization of the thermoelectric thin films are also described in this chapter. Finally, a few of the prototypes of thermoelectric thin films (made of bismuth and antimony tellurides, {Bi}2{Te}3, and {Sb}2{Te}3, respectively) obtained by co-evaporation (using the custom made deposition chamber) and characterized for quality assessment are dealt with. All the issues involved in the co-evaporation and characterization are objects of analysis in this chapter.

  9. Calorimetry of epitaxial thin films

    SciTech Connect

    Cooke, David W.; Hellman, F. [Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300 (United States); Groves, J. R.; Clemens, B. M. [Department of Materials Science, Stanford University, Stanford, California 94305 (United States); Moyerman, S.; Fullerton, E. E. [Center for Magnetic Recording Research, University of California at San Diego, La Jolla, California 92093-0401 (United States)

    2011-02-15

    Thin film growth allows for the manipulation of material on the nanoscale, making possible the creation of metastable phases not seen in the bulk. Heat capacity provides a direct way of measuring thermodynamic properties of these new materials, but traditional bulk calorimetric techniques are inappropriate for such a small amount of material. Microcalorimetry and nanocalorimetry techniques exist for the measurements of thin films but rely on an amorphous membrane platform, limiting the types of films which can be measured. In the current work, ion-beam-assisted deposition is used to provide a biaxially oriented MgO template on a suspended membrane microcalorimeter in order to measure the specific heat of epitaxial thin films. Synchrotron x-ray diffraction showed the biaxial order of the MgO template. X-ray diffraction was also used to prove the high quality of epitaxy of a film grown onto this MgO template. The contribution of the MgO layer to the total heat capacity was measured to be just 6.5% of the total addenda contribution. The heat capacity of a Fe{sub .49}Rh{sub .51} film grown epitaxially onto the device was measured, comparing favorably to literature data on bulk crystals. This shows the viability of the MgO/SiN{sub x}-membrane-based microcalorimeter as a way of measuring the thermodynamic properties of epitaxial thin films.

  10. Thin-film metal hydrides.

    PubMed

    Remhof, Arndt; Borgschulte, Andreas

    2008-12-01

    The goal of the medieval alchemist, the chemical transformation of common metals into nobel metals, will forever be a dream. However, key characteristics of metals, such as their electronic band structure and, consequently, their electric, magnetic and optical properties, can be tailored by controlled hydrogen doping. Due to their morphology and well-defined geometry with flat, coplanar surfaces/interfaces, novel phenomena may be observed in thin films. Prominent examples are the eye-catching hydrogen switchable mirror effect, the visualization of solid-state diffusion and the formation of complex surface morphologies. Thin films do not suffer as much from embrittlement and/or decrepitation as bulk materials, allowing the study of cyclic absorption and desorption. Therefore, thin-metal hydride films are used as model systems to study metal-insulator transitions, for high throughput combinatorial research or they may be used as indicator layers to study hydrogen diffusion. They can be found in technological applications as hydrogen sensors, in electrochromic and thermochromic devices. In this review, we discuss the effect of hydrogen loading of thin niobium and yttrium films as archetypical examples of a transition metal and a rare earth metal, respectively. Our focus thereby lies on the hydrogen induced changes of the electronic structure and the morphology of the thin films, their optical properties, the visualization and the control of hydrogen diffusion and on the study of surface phenomena and catalysis. PMID:18980236

  11. Simple vortex states in films of type-I Ginzburg-Landau superconductor

    NASA Astrophysics Data System (ADS)

    Sweeney, Mark C.; Gelfand, Martin P.

    2010-12-01

    Sufficiently thin films of type-I superconductor in a perpendicular magnetic field exhibit a triangular vortex lattice while thick films develop an intermediate state. To elucidate what happens between these two regimes, precise numerical calculations have been made within Ginzburg-Landau theory at ?=0.5 and 0.25 for a variety of vortex lattice structures with one flux quantum per unit cell. The phase diagram in the space of mean induction and film thickness includes a narrow wedge in which a square lattice is stable, surrounded by the domain of stability of the triangular lattice at thinner films/lower fields and, on the other side, rectangular lattices with continuously varying aspect ratio. The vortex lattice has an anomalously small shear modulus within and close to the square lattice phase. Solutions of the Ginzburg-Landau equations have been obtained by similar calculations for bulk systems and thin films with one vortex but two flux quanta per square or triangular unit cell. Primitive lattices of double-fluxoid vortices are thermodynamically unstable in bulk in both type-I and type-II superconductors, as expected. In type-I films these double-fluxoid lattices do not pre-empt the single-fluxoid lattice structures.

  12. (Thin films under chemical stress)

    SciTech Connect

    Not Available

    1990-01-01

    As stated above the purpose of this research is to enable workers in a variety of fields to understand the chemical and physical changes which take place when thin films (primarily organic films) are placed under chemical stress. This stress may occur because the film is being swelled by penetrant entrained in solvent, because interfacial reactions are occurring at one or more boundaries within the film structure, or because some component of the film is responding to an external stimulus (e.g. pH, temperature, electric field, or radiation). These questions are important within the context of our long-term goal of understanding the behavior of composite structures, composed of thin organic polymer films interspersed with Langmuir-Blodgett (LB) and self-assembled monolayers, which might have unique functional properties. In the past year we have concentrated on the following objectives: (1) understanding how the two possible diffusion mechanisms contribute to the swelling of thin films of organic polymers place in solution, (2) identifying systems which are appropriate polymer media for the construction of composite membranes for use in aqueous environments, and (3) understanding the self-assembly process for long chain fatty acids at model surfaces. Progress in meeting each of these objectives will be described in this report. 4 figs.

  13. Optical and electrical properties of thin superconducting films

    NASA Technical Reports Server (NTRS)

    Covington, Billy C.; Jing, Feng Chen

    1990-01-01

    Infrared spectroscopic techniques can provide a vital probe of the superconducting energy gap which is one of the most fundamental physical properties of superconductors. Currently, the central questions regarding the optical properties of superconductors are how the energy gap can be measured by infrared techniques and at which frequency the gap exists. An effective infrared spectroscopic method to investigate the superconducting energy gap, Eg, was developed by using the Bomem DA 3.01 Fourier Transformation Spectrophotometer. The reflectivity of a superconducting thin film of YBaCuO deposited on SrTiO3 was measured. A shoulder was observed in the superconducting state reflectance R(sub S) at 480/cm. This gives a value of Eg/kT(sub c) = 7.83, where k is the Boltzmann constant and T(sub c) is the superconducting transition temperature, from which, it is suggested that YBaCuO is a very strong coupling superconductor.

  14. Low work function, stable thin films

    DOEpatents

    Dinh, Long N. (Concord, CA); McLean, II, William (Oakland, CA); Balooch, Mehdi (Berkeley, CA); Fehring, Jr., Edward J. (Dublin, CA); Schildbach, Marcus A. (Livermore, CA)

    2000-01-01

    Generation of low work function, stable compound thin films by laser ablation. Compound thin films with low work function can be synthesized by simultaneously laser ablating silicon, for example, and thermal evaporating an alkali metal into an oxygen environment. For example, the compound thin film may be composed of Si/Cs/O. The work functions of the thin films can be varied by changing the silicon/alkali metal/oxygen ratio. Low work functions of the compound thin films deposited on silicon substrates were confirmed by ultraviolet photoelectron spectroscopy (UPS). The compound thin films are stable up to 500.degree. C. as measured by x-ray photoelectron spectroscopy (XPS). Tests have established that for certain chemical compositions and annealing temperatures of the compound thin films, negative electron affinity (NEA) was detected. The low work function, stable compound thin films can be utilized in solar cells, field emission flat panel displays, electron guns, and cold cathode electron guns.

  15. Nanomechanical properties of hydrated organic thin films

    E-print Network

    Choi, Jae Hyeok

    2007-01-01

    Hydrated organic thin films are biological or synthetic molecularly thin coatings which impart a particular functionality to an underlying substrate and which have discrete water molecules associated with them. Such films ...

  16. FRAP in thin film flows

    NASA Astrophysics Data System (ADS)

    Wexler, Jason; Jacobi, Ian; Stone, Howard

    2013-11-01

    A new technique is proposed for measuring the velocity field within thin liquid films, which combines Fluorescence Recovery After Photobleaching (FRAP) measurements with two-dimensional Taylor dispersion analysis. FRAP is a technique used largely by biologists to measure the diffusion coefficient of compounds in living cells. A small spot of fluorescent dye is bleached and then monitored for subsequent fluorescence recovery. The rate of recovery can be related to the coefficient of molecular diffusion. In our experiments we apply FRAP to a flowing liquid film, where advection, in addition to molecular diffusion, contributes to the evolution of the bleached spot. By employing simple optical measurements of the rate of advection and diffusion, combined with an analysis of dispersion, we can uniquely determine the velocity profile within a thin film. As a proof of concept we apply this technique to shear-driven flow over a liquid film within a micro-patterned surface.

  17. Characterization of sculptured thin films

    SciTech Connect

    Ryan, Joseph V.; Horn, Mark; Lakhtakia, Ashlesh; Pantano, C. G.

    2004-05-11

    Physical vapor deposition can be used to synthesize sculptured thin films with high surface areas. Highly directional vapor deposition onto a tilted, rotating substrate has been shown to produce nanostructured materials with controlled columnar features, including zig-zag, cusp, chevron, and helical geometries. Nanoporous coatings such as these are desirable for optical sensing applications due to their accessible high surface area, but few techniques are available to quantify the surface area of thin films. Electron beam and thermal evaporation techniques are used to synthesize highly porous thin films from silicon dioxide and a germanium antimony selenide chalcogenide glass in order to explore their potential for optical applications in both the visible and infrared spectral ranges. Characterization has been performed using nitrogen adsorption isotherms obtained with a quartz crystal microbalance. It is shown that surface area can be increased up to 375 times that of a flat film by deposition at oblique angles. A nitrogen adsorption technique is introduced as a means to examine the porosity of sculptured thin films at a nanoscale.

  18. Thermopower of thin iron films

    NASA Astrophysics Data System (ADS)

    Schepis, Randy; Schröder, Klaus

    1992-02-01

    Thin iron films were prepared by evaporation in a high vacuum system (pressure in the 10 -5 MPa range). The thermopower was measured in situ near room temperature as a function of film thickness. Iron films with rather high resistivity values showed a strong thickness effect of the Seeback coefficient, S, with the difference between S (bulk) and S (film) reaching values of up to (19±3) ?V/K for a sample 5 nm thick. The difference between S (bulk) and S (film) decreased with increasing d values. However, a sample with a resistance value of 50 ?? cm at d = 5 n had an S value which differed by less than 3 ?V/K from S (bulk).

  19. Lessons from Oxypnictide Thin Films

    NASA Astrophysics Data System (ADS)

    Haindl, Silvia; Kidszun, Martin; Onken, Franziska; Mietke, Alexander; Thersleff, Thomas

    2013-02-01

    First experiments on the growth of oxypnictide F-doped LaFeAsO thin films indicated an incomplete normal-to-superconducting transition and offered a work programme challenging to overcome possible difficulties in their fabrication. In this regard the possibility of an all in-situ epitaxial growth appeared to be a matter of time and growth parameters. The following review clarifies that F-doped oxypnictide thin films are extremely difficult to grow by in-situ PLD due to the formation of very stable impurity phases such as oxyfluorides (LaOF) and oxides (La2O3) and the loss of stoichiometry possibly due to incongruent evaporation of the target or re-evaporation of volatile elements at the substrate surface. However, the review also demonstrates that the employed two-step fabrication process for oxypnictide thin films has been successfully applied in the preparation of clean polycrystalline as well as of epitaxial thin films. Fundamental investigations on the upper critical field, its temperature dependence and its anisotropy contributed to an understanding of multiband superconductivity in oxypnictides.

  20. Thin film polymeric gel electrolytes

    DOEpatents

    Derzon, Dora K. (1554 Rosalba St. NE., Albuquerque, Bernalillo County, NM 87112); Arnold, Jr., Charles (3436 Tahoe, NE., Albuquerque, Bernalillo County, NM 87111); Delnick, Frank M. (9700 Fleming Rd., Dexter, MI 48130)

    1996-01-01

    Novel hybrid thin film electrolyte, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities .apprxeq.10.sup.-3 .OMEGA..sup.-1 cm.sup.-1 are useful as electrolytes for rechargeable lithium batteries.

  1. Thin film polymeric gel electrolytes

    DOEpatents

    Derzon, D.K.; Arnold, C. Jr.; Delnick, F.M.

    1996-12-31

    Novel hybrid thin film electrolytes, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities {approx_equal}10{sup {minus}3}{Omega}{sup {minus}1} cm{sup {minus}1} are useful as electrolytes for rechargeable lithium batteries. 1 fig.

  2. Thin Film Piezoelectrics for MEMS

    Microsoft Academic Search

    S. Trolier-McKinstry; P. Muralt

    2004-01-01

    Thin film piezoelectric materials offer a number of advantages in microelectromechanical systems (MEMS), due to the large motions that can be generated, often with low hysteresis, the high available energy densities, as well as high sensitivity sensors with wide dynamic ranges, and low power requirements. This paper reviews the literature in this field, with an emphasis on the factors that

  3. Thin-film multilayer interconnect technology for YBa2Cu3O7 - x

    Microsoft Academic Search

    F. C. Wellstood; J. J. Kingston; John Clarke

    1994-01-01

    The construction of microelectronic circuits from high-transition-temperature (Tc) superconductors requires techniques for producing thin-film wires, insulating crossovers, and vias (window contacts) between wires. Together, these three components form a superconducting interconnect technology. The challenges encountered in developing such a technology for high-Tc superconductors involve factors associated with the materials, the circuits and the fabrication techniques. The use of pulsed laser

  4. Thin films and uses

    DOEpatents

    Baskaran, Suresh (Kennewick, WA); Graff, Gordon L. (Kennewick, WA); Song, Lin (Richland, WA)

    1998-01-01

    The invention provides a method for synthesizing a titanium oxide-containing film comprising the following steps: (a) preparing an aqueous solution of a titanium chelate with a titanium molarity in the range of 0.01M to 0.6M. (b) immersing a substrate in the prepared solution, (c) decomposing the titanium chelate to deposit a film on the substrate. The titanium chelate maybe decomposed acid, base, temperature or other means. A preferred method provides for the deposit of adherent titanium oxide films from C2 to C5 hydroxy carboxylic acids. In another aspect the invention is a novel article of manufacture having a titanium coating which protects the substrate against ultraviolet damage. In another aspect the invention provides novel semipermeable gas separation membranes, and a method for producing them.

  5. Effects of post-annealing on the infrared active phonon modes of low anisotropy ( ?=5-11) Cu 1- xTl xBa 2Ca 2Cu 3O 10- ? superconductor thin films

    NASA Astrophysics Data System (ADS)

    Khan, Nawazish A.; Khurram, A. A.; Mazhar, M.

    2004-08-01

    The effects of post-annealing conditions on the apical oxygen phonon modes have been investigated and their correlations with the critical temperature of the Cu 1- xTl xBa 2Ca 2Cu 3O 10- ? (Cu 1- xTl x-1223) superconductor thin films have been developed. The samples were annealed in different ambient environments, such as air, N 2, O 2 and vacuum and their FTIR absorption spectrum has been taken. Three absorption peaks observed between 455-440, 665-648 and 1240-1246 cm -1 are assigned to apical oxygen vibrations, the chain axis O(3) vibrations and to C-O single-bond, respectively. The frequency of the mode at 655 cm -1 is sensitive to the concentration of O(3) in the charge reservoir layer, which in turn controls increase or decrease of the bond length of apical oxygen. The softening of the apical oxygen mode is possibly linked with the reduction of thallium, which in turn is associated with the amount of oxygen [O(3)] in the charge reservoir layer. In as-prepared material and annealed under oxygen, the state of thallium is not reduced from Tl +3 to Tl +1 and sufficient number of carriers are not supplied to CuO 2 planes, the material remains in the region of carrier under-doping. The softening of apical oxygen mode positioned at 455 cm -1 is associated with the formation of low Tc phases. The C-O related IR mode is softened with the post-annealing in air at 780 °C and annealing in N 2 ambient at 400 °C. The critical transition temperature is found to decrease with the post-annealing at 400 °C in N 2, which is possibly due to the under-doped CuO 2 planes of the material. However, the post-annealing at 780 and 650 °C increases Tc (mid-point) to 107 and 111 K respectively.

  6. Multiferroic thin films

    Microsoft Academic Search

    Wilma Eerenstein; Finlay Morrison

    2005-01-01

    Multiferroic materials are both ferroelectric and ferromagnetic. This combination opens up new applications, as the magnetization can be addressed with an electric field and the polarization by a magnetic field. However, most multiferroic materials either have low polarizations and\\/or low transition temperatures, thus limiting their potential use in novel devices. We report on high quality epitaxial films of two candidate

  7. Ion-beam-induced texturing in oxide thin films and its applications

    Microsoft Academic Search

    Pin-Chin Connie Wang

    1999-01-01

    Ion-beam-assisted deposition (IBAD) has been demonstrated to be one of the most promising methods to artificially control thin films' texture. Recent years, much research has been conducted to try to control the in-plane alignment in oxide films for the high Tc superconductor YBa 2Cu3O7-x (HTS YBCO) power applications. The IBAD films deposited on engineering substrate can potentially replace the single

  8. Thin-Film Metamaterials called Sculptured Thin Films

    E-print Network

    Lakhtakia, Akhlesh

    2010-01-01

    Morphology and performance are conjointed attributes of metamaterials, of which sculptured thin films (STFs) are examples. STFs are assemblies of nanowires that can be fabricated from many different materials, typically via physical vapor deposition onto rotating substrates. The curvilinear--nanowire morphology of STFs is determined by the substrate motions during fabrication. The optical properties, especially, can be tailored by varying the morphology of STFs. In many cases prototype devices have been fabricated for various optical, thermal, chemical, and biological applications.

  9. Thin-Film Metamaterials Called Sculptured Thin Films

    Microsoft Academic Search

    Akhlesh Lakhtakia; Joseph B. Geddes III

    2010-01-01

    \\u000a Morphology and performance are conjointed attributes of metamaterials, of which sculptured thin films (STFs) are examples.\\u000a STFs are assemblies of nanowires that can be fabricated from many different materials, typically via physical vapor deposition\\u000a onto rotating substrates. The curvilinear-nanowire morphology of STFs is determined by the substrate motions during fabrication.\\u000a The optical properties, especially, can be tailored by varying the

  10. high-k thin films

    NASA Astrophysics Data System (ADS)

    Sahiner, M. A.; Lysaght, P. S.; Price, J.; Kirsch, P. D.; Woicik, J. C.; Klump, A.; Reehil, C.; Manners, W. A.; Nabizadeh, A.

    2014-10-01

    The local symmetries around the Hf sites in thin films of Hf1- x Zr x O2/Si(100) were probed using grazing incidence extended X-ray absorption fine-structure spectroscopy (EXAFS). The effects of the Zr incorporation on the local crystal symmetries were investigated using Hf L3 EXAFS at the Beamline X23A2 of the Brookhaven National Laboratory. The Zr ratios in the various films were set to between 0.0 and 1.0. Significant changes in the local environment were observed for x = 0.25 or greater values. For x = 0.0, the film local structure around Hf sites remain in the equilibrium monoclinic phase as referenced from our previous studies on HfO2 thin films on Si(100). When Zr is introduced, tetragonal symmetry around the Hf atom appears and becomes dominant at x = 0.63. Using the EXAFS theoretical simulations and non-linear least-square fit results, the fractions of the monoclinic versus tetragonal phases were identified in each film.

  11. Thin film buried anode battery

    DOEpatents

    Lee, Se-Hee (Lakewood, CO); Tracy, C. Edwin (Golden, CO); Liu, Ping (Denver, CO)

    2009-12-15

    A reverse configuration, lithium thin film battery (300) having a buried lithium anode layer (305) and process for making the same. The present invention is formed from a precursor composite structure (200) made by depositing electrolyte layer (204) onto substrate (201), followed by sequential depositions of cathode layer (203) and current collector (202) on the electrolyte layer. The precursor is subjected to an activation step, wherein a buried lithium anode layer (305) is formed via electroplating a lithium anode layer at the interface of substrate (201) and electrolyte film (204). The electroplating is accomplished by applying a current between anode current collector (201) and cathode current collector (202).

  12. Bismuth ferrite composite thin films

    NASA Astrophysics Data System (ADS)

    Wu, Jiagang; Zhang, Binyu; Wang, Xiaopeng

    2013-06-01

    0.60Bi0.90La0.10FeO3-0.40Pb(Zr0.52Ti0.48)O3 composite thin films were deposited on Pt/TiO2/SiO2/Si(100) substrates by radio-frequency sputtering and their ferroelectric and fatigue properties were mainly investigated. The composite thin films have a low dielectric loss, a high dielectric constant, and enhanced ferroelectric properties of 2 P r˜122.6 ?C/cm2 and 2 E c˜479.3 kV/cm, together with a fatigue-free behavior at 200 kHz. Their fatigue behavior is strongly dependent on measurement frequencies, and the concentration of oxygen vacancies plays an important role in their fatigue behavior.

  13. in thin film solar cells

    Microsoft Academic Search

    M. Igalson; P. Zabierowski; A. Romeo; L. Stolt

    The interface states in TCO\\/CdS\\/CdTe and ZnO\\/CdS\\/Cu(In,Ga)Se2 photovoltaic devices has been studied by use of reverse-bias transient capacitance spectroscopy. Laplace transform analysis has been used in order to enhance a spectral resolution of the technique. It is shown, that the method yields useful information on the electronic characteristics of the heterointerface in the thin film solar cells. The conclusions include

  14. Electrochemical mediated thin film growth

    Microsoft Academic Search

    Stanko Radovan Brankovic

    1999-01-01

    Electrochemical single crystal thin film growth in the heteroepitaxial system silver on gold (Ag\\/Au(111)) was investigated using a novel approach. A new electrodeposition technique was developed, which produces atomically flat epitaxial metal overlayers of quality similar to that obtained using ultra high vacuum techniques. In the first case, a metal of interest such as Ag is co-deposited with a reversibly

  15. SUPERCONDUCTING PROPERTIES OF ALUMINIUM THIN FILMS AFTER ION IMPLANTATION AT LIQUID HELIUM TEMPERATURES (*)

    E-print Network

    Boyer, Edmond

    L-271 SUPERCONDUCTING PROPERTIES OF ALUMINIUM THIN FILMS AFTER ION IMPLANTATION AT LIQUID HELIUM concentration near AlH2. It is well-known [1] that the superconducting transition temperature Tc of metals as in the electronic density of states N(O) at the Fermi surface. In the case of weak-coupling superconductors

  16. Thin-Film Silicon PV Technology

    Microsoft Academic Search

    Miroslav Zeman

    2010-01-01

    Thin-film silicon solar cell technology is one of the promising photovoltaic technologies for delivering low-cost solar electricity. Today the thin-film silicon PV market (402MWp produced in 2008) is dominated by amorphous silicon based modules; however it is expected that the tandem amorphous\\/microcrystalline silicon modules will take over in near future. Solar cell structures based on thin-film silicon for obtaining high

  17. Alternative Dewetting Pathways of Thin Liquid Films

    E-print Network

    Klein, Jacob

    Klein2 An alternative pathway for the initiation of dewetting in thin metastable films of partially, , is predicted to vary strongly with the film thick- ness h0 as h0 5 . Heterogeneous nucleation is expected

  18. The interplay between spatially separated ferromagnetic and superconducting thin films

    E-print Network

    Sullivan, Isaac John

    2013-02-22

    thin film and allowed to oxidize in order to produce a thin insulating layer. Finally, two superconducting thin films of nearly equal thickness were evaporated via physical vapor deposition onto the A1?O ? insulating layer. Both superconducting films...

  19. The interplay between spatially separated ferromagnetic and superconducting thin films 

    E-print Network

    Sullivan, Isaac John

    2013-02-22

    thin film and allowed to oxidize in order to produce a thin insulating layer. Finally, two superconducting thin films of nearly equal thickness were evaporated via physical vapor deposition onto the A1?O? insulating layer. Both superconducting films...

  20. Thin film solar energy collector

    DOEpatents

    Aykan, Kamran (Monmouth Beach, NJ); Farrauto, Robert J. (Westfield, NJ); Jefferson, Clinton F. (Millburn, NJ); Lanam, Richard D. (Westfield, NJ)

    1983-11-22

    A multi-layer solar energy collector of improved stability comprising: (1) a substrate of quartz, silicate glass, stainless steel or aluminum-containing ferritic alloy; (2) a solar absorptive layer comprising silver, copper oxide, rhodium/rhodium oxide and 0-15% by weight of platinum; (3) an interlayer comprising silver or silver/platinum; and (4) an optional external anti-reflective coating, plus a method for preparing a thermally stable multi-layered solar collector, in which the absorptive layer is undercoated with a thin film of silver or silver/platinum to obtain an improved conductor-dielectric tandem.

  1. Electrostatic thin film chemical and biological sensor

    DOEpatents

    Prelas, Mark A. (Columbia, MO); Ghosh, Tushar K. (Columbia, MO); Tompson, Jr., Robert V. (Columbia, MO); Viswanath, Dabir (Columbia, MO); Loyalka, Sudarshan K. (Columbia, MO)

    2010-01-19

    A chemical and biological agent sensor includes an electrostatic thin film supported by a substrate. The film includes an electrostatic charged surface to attract predetermined biological and chemical agents of interest. A charge collector associated with said electrostatic thin film collects charge associated with surface defects in the electrostatic film induced by the predetermined biological and chemical agents of interest. A preferred sensing system includes a charge based deep level transient spectroscopy system to read out charges from the film and match responses to data sets regarding the agents of interest. A method for sensing biological and chemical agents includes providing a thin sensing film having a predetermined electrostatic charge. The film is exposed to an environment suspected of containing the biological and chemical agents. Quantum surface effects on the film are measured. Biological and/or chemical agents can be detected, identified and quantified based on the measured quantum surface effects.

  2. Thin film characterization by acoustic microscopy

    Microsoft Academic Search

    Tribmram Kundu

    1997-01-01

    In this paper a brief review of the recent applications of acoustic microscopes for material property determination of thin films is given. Acoustic microscopes generate Rayleigh waves near the surface (up to one or two wave length depth) of the specimen under inspection. Since the Rayleigh wave speed is sensitive to thin film properties such as Young's modulus, Poission's ratio,

  3. Multiferroics: progress and prospects in thin films

    Microsoft Academic Search

    R. Ramesh; Nicola A. Spaldin

    2007-01-01

    Multiferroic materials, which show simultaneous ferroelectric and magnetic ordering, exhibit unusual physical properties - and in turn promise new device applications - as a result of the coupling between their dual order parameters. We review recent progress in the growth, characterization and understanding of thin-film multiferroics. The availability of high-quality thin-film multiferroics makes it easier to tailor their properties through

  4. Magnetic Structure of Engineered Multiferroic Thin Films

    Microsoft Academic Search

    Xianglin Ke

    2011-01-01

    The intriguing properties of multiferroics, i.e., materials exhibiting the coexistence of magnetism and ferroelectricity, have stimulated intense research interest in recent years. From the viewpoint of practical applications, one needs to exploit the thin film architectures of multiferroic materials. However, fewer studies have addressed the magnetic structures of multiferroic thin films. I will present recent experimental works on two multiferroic

  5. Thin film shape memory alloy microactuators

    Microsoft Academic Search

    P. Krulevitch; A. P. Lee; P. B. Ramsey; J. C. Trevino; M. A. Northrup

    1996-01-01

    Thin film shape memory alloys (SMAs) have the potential to become a primary actuating mechanism for mechanical devices with dimensions in the micron-to-millimeter range requiring large forces over long displacements. The work output per volume of thin film SMA microactuators exceeds that of other microactuation mechanisms such as electrostatic, magnetic, thermal bimorph, piezoelectric, and thermopneumatic, and it is possible to

  6. ORIGINAL PAPER Nanocrystalline Diamond Thin Films Synthesis

    E-print Network

    Qin, Qinghua

    ­4]. They have been synthesized by various CVD technologies, such as DCPJCVD [5, 6], Pulsed laser deposition (PLD, 17] only synthesized small size micron level curved surface diamond thin films by HF-CVD. This mightORIGINAL PAPER Nanocrystalline Diamond Thin Films Synthesis on Curved Surface Duosheng Li · Qing H

  7. Preparation and evaluation of ferroelectric thin films

    SciTech Connect

    Ogawa, Toshio [Shizuoka Institute of Science and Technology, Fukuroi (Japan)

    1994-12-31

    The stoichiometry of film compositions prepared by RF magnetron sputtering and laser ablation is discussed. Control of the crystal orientation of the films was determined from the relation between the films and substrates. In addition, a new bottom electrode material in place of platinum was developed for use with ferroelectric thin films. The ferroelectric properties and fatigue behavior of the films were evaluated with the new electrodes.

  8. Cellulose triacetate, thin film dielectric capacitor

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (inventor); Jow, T. Richard (inventor)

    1993-01-01

    Very thin films of cellulose triacetate are cast from a solution containing a small amount of high boiling temperature, non-solvent which evaporates last and lifts the film from the casting surface. Stretched, oriented, crystallized films have high electrical breakdown properties. Metallized films less than about 2 microns in thickness form self-healing electrodes for high energy density, pulsed power capacitors. Thicker films can be utilized as a dielectric for a capacitor.

  9. Cellulose triacetate, thin film dielectric capacitor

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (inventor); Jow, T. Richard (inventor)

    1995-01-01

    Very thin films of cellulose triacetate are cast from a solution containing a small amount of high boiling temperature, non-solvent which evaporates last and lifts the film from the casting surface. Stretched, oriented, crystallized films have high electrical breakdown properties. Metallized films less than about 2 microns in thickness form self-healing electrodes for high energy density, pulsed power capacitors. Thicker films can be utilized as a dielectric for a capacitor.

  10. A monolithic thin film electrochromic window

    SciTech Connect

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K. (Tufts Univ., Medford, MA (United States). Electro-Optics Technology Center); Wei, G. (Mobil Solar Energy Corp., Billerica, MA (United States)); Yu, P.C. (PPG Industries, Inc., Monroeville, PA (United States))

    1991-01-01

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors' institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  11. Magnetostrictive thin films for microwave spintronics.

    PubMed

    Parkes, D E; Shelford, L R; Wadley, P; Holý, V; Wang, M; Hindmarch, A T; van der Laan, G; Campion, R P; Edmonds, K W; Cavill, S A; Rushforth, A W

    2013-01-01

    Multiferroic composite materials, consisting of coupled ferromagnetic and piezoelectric phases, are of great importance in the drive towards creating faster, smaller and more energy efficient devices for information and communications technologies. Such devices require thin ferromagnetic films with large magnetostriction and narrow microwave resonance linewidths. Both properties are often degraded, compared to bulk materials, due to structural imperfections and interface effects in the thin films. We report the development of epitaxial thin films of Galfenol (Fe81Ga19) with magnetostriction as large as the best reported values for bulk material. This allows the magnetic anisotropy and microwave resonant frequency to be tuned by voltage-induced strain, with a larger magnetoelectric response and a narrower linewidth than any previously reported Galfenol thin films. The combination of these properties make epitaxial thin films excellent candidates for developing tunable devices for magnetic information storage, processing and microwave communications. PMID:23860685

  12. Thin film passive ring resonator laser gyro

    SciTech Connect

    Segre, J.P.; Haavisto, J.R.

    1987-04-14

    This patent describes a thin film laser gyro comprising: a solid state laser; a thin film passive ring resonator; a thin film delivery loop waveguide means evanescently coupled to the resonator to deliver light from the laser into the resonator; a thin film electro-optic switch means to alternatingly inject a clockwise and a counterclockwise beam of light from the laser into the delivery loop; and a thin film electro-optic modulator means to modulate the phase of light from the laser to maintain the clockwise and the counterclockwise beams on resonance independently. The electro-optic modulator means comprises a channel waveguide of an electro-optic material with electrodes for modulating the phase of light from the laser.

  13. A monolithic thin film electrochromic window

    SciTech Connect

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K. [Tufts Univ., Medford, MA (United States). Electro-Optics Technology Center; Wei, G. [Mobil Solar Energy Corp., Billerica, MA (United States); Yu, P.C. [PPG Industries, Inc., Monroeville, PA (United States)

    1991-12-31

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors` institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  14. Magnetostrictive thin films for microwave spintronics

    PubMed Central

    Parkes, D. E.; Shelford, L. R.; Wadley, P.; Holý, V.; Wang, M.; Hindmarch, A. T.; van der Laan, G.; Campion, R. P.; Edmonds, K. W.; Cavill, S. A.; Rushforth, A. W.

    2013-01-01

    Multiferroic composite materials, consisting of coupled ferromagnetic and piezoelectric phases, are of great importance in the drive towards creating faster, smaller and more energy efficient devices for information and communications technologies. Such devices require thin ferromagnetic films with large magnetostriction and narrow microwave resonance linewidths. Both properties are often degraded, compared to bulk materials, due to structural imperfections and interface effects in the thin films. We report the development of epitaxial thin films of Galfenol (Fe81Ga19) with magnetostriction as large as the best reported values for bulk material. This allows the magnetic anisotropy and microwave resonant frequency to be tuned by voltage-induced strain, with a larger magnetoelectric response and a narrower linewidth than any previously reported Galfenol thin films. The combination of these properties make epitaxial thin films excellent candidates for developing tunable devices for magnetic information storage, processing and microwave communications. PMID:23860685

  15. Raman spectroscopy of thin films

    NASA Astrophysics Data System (ADS)

    Burgess, James Shaw

    Raman spectroscopy was used in conjunction with x-ray diffraction and x-ray photoelectron spectroscopy to elucidate structural and compositional information on a variety of samples. Raman was used on the unique La 2NiMnO6 mixed double perovskite which is a member of the LaMnO3 family of perovskites and has multiferroic properties. Raman was also used on nanodiamond films as well as some boron-doped carbon compounds. Finally, Raman was used to identify metal-dendrimer bonds that have previously been overlooked. Vibrational modes for La2NiMnO6 were ascribed by comparing spectra with that for LaMnO3 bulk and thin film spectra. The two most prominent modes were labeled as an asymmetric stretch (A g) centered around 535 cm-1 and a symmetric stretch (B g) centered around 678 cm. The heteroepitaxial quality of La2NiMnO 6 films on SrTiO3 (100) and LaAlO3 (100) substrates were examined using the Raman microscope by way of depth profile experiments and by varying the thickness of the films. It was found that thin films (10 nm) had much greater strain on the LaAlO3 substrate than on the SrTiO3 substrate by examining the shifts of the Ag and the Bg modes from their bulk positions. Changes in the unit cell owing to the presence of oxygen defects were also monitored using Raman spectroscopy. It was found that the Ag and Bg modes shifted between samples formed with different oxygen partial pressures. These shifts could be correlated to changes in the symmetry of the manganese centers due to oxygen defects. Raman spectroscopy was used to examine the structural and compositional characteristics of carbon materials. Nanocrystalline diamond coated cutting tools were examined using the Raman Microscope. Impact, abrasion, and depth profile experiments indicated that delamination was the primary cause of film failure in these systems. Boron doped material of interest as catalyst supports were also examined. Monitoring of the G-mode and intensities of the D- and G-modes indicated that boron was successfully introduced into both a bulk powder fabricated in a quartz furnace using a BCl3/C6H 6 precursor and for a thin film (30 nm) deposited in a vacuum chamber using d.c. magnetron cosputtering. In addition to Raman, x-ray diffraction and x-ray photoelectron spectroscopy were used to verify boron-doping of the materials. Generation 4 Poly(amidoamine) dendrimers were used to form platinum and cobalt nanoparticles to form dendrimer-encapsulated nanoparticles (DENs). It was seen using both Raman and infrared spectroscopy that these metals bonded with the dendrimers after reduction. These studies highlight the efficacy of Raman in the study of a wide variety of materials to obtain both compositional and structural information.

  16. Thin Film Inductor with Multilayer Magnetic Core

    Microsoft Academic Search

    K. Shirakawa; H. Kurata; M. Kasuya; S. Ohnuma; J. Toryu; K. Murakami

    1993-01-01

    In this work, thin film microinductors were investigated from the standpoint of increasing the quality factor (Q) and inductance (L). To obtain a high Q, it is important to use a magnetic core with a small iron loss at high frequencies. Thin film microinductors were prepared using multilayered CoNbZr\\/AlN film. The optimum conditions for a high Q were investigated by

  17. Infrared radiation of thin plastic films.

    NASA Technical Reports Server (NTRS)

    Tien, C. L.; Chan, C. K.; Cunnington, G. R.

    1972-01-01

    A combined analytical and experimental study is presented for infrared radiation characteristics of thin plastic films with and without a metal substrate. On the basis of the thin-film analysis, a simple analytical technique is developed for determining band-averaged optical constants of thin plastic films from spectral normal transmittance data for two different film thicknesses. Specifically, the band-averaged optical constants of polyethylene terephthalate and polyimide were obtained from transmittance measurements of films with thicknesses in the range of 0.25 to 3 mil. The spectral normal reflectance and total normal emittance of the film side of singly aluminized films are calculated by use of optical constants; the results compare favorably with measured values.

  18. Magnetic Character of Very Thin Permalloy Films

    Microsoft Academic Search

    F. B. Humphrey

    1963-01-01

    The quasistatic magnetic characteristics of thin Permalloy films have been investigated using a sensitive automatic magnetic torque balance. The most striking feature of the many films investigated in the thickness range below 250 Å is their similarity to thicker films. The data for K are essentially constant until about 80 Å where it drops quickly and smoothly to zero at

  19. Critical state in a circular two-dimensional superconductor and magnetization of thin Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4{minus}{delta}} and YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films in a transverse field

    SciTech Connect

    Kuznetsov, A.V.; Ivanov, A.A.; Eremenko, D.V. [Department of Quantum Electronics, Moscow Engineering Physics Institute, Kashirskoe shosse 31, 115409, Moscow (Russian Federation)] [Department of Quantum Electronics, Moscow Engineering Physics Institute, Kashirskoe shosse 31, 115409, Moscow (Russian Federation); Trofimov, V.N. [Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980, Dubna, Moscow region (Russian Federation)] [Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980, Dubna, Moscow region (Russian Federation)

    1995-10-01

    Precise measurements of the magnetization of circular epitaxial Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4{minus}{delta}} and YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films in a transverse magnetic field are performed and analyzed within the framework of the recently presented critical state model (CSM) in the two-dimensional superconductor. Restrictions on the reliability of the model are considered. It has been found that the original CSM, based on Bean`s limitation on the critical current density {ital J}{sub {ital c}}=const, describes well the temperature and field dependences of the film magnetization in a low field (until the full disappearance of the flux-free region in the film) under the condition {ital B}{sup *}{much_gt}{mu}{sub 0}{ital dJ}{sub {ital c}}ln({radical}{ital Rd} /{lambda}), where {ital B}{sup *} is the characteristic field of the critical current drop in a strong field, {lambda} is the penetration depth, {ital d} is the thickness, and {ital R} is the radius of the film, respectively. In the strong field an exponential or power suppression of the critical current is observed and the model under question is extended to this region. The problem of a lower critical field related to thin films is also discussed. The paramagnetic response demonstrated by all our films in field-cooled measurements, which has much in common with the Wohlleben effect, was investigated and the conclusion was drawn that this artifact is caused by the temperature-dependent stray field of the magnetometer parts.

  20. Crystallization of thin and ultra-thin polymer films

    NASA Astrophysics Data System (ADS)

    Wang, Yantian

    Thin and ultra-thin polymer films have received great interest due to their technological applications in the modern micro-electronic devices. It has been demonstrated that the presence of the interface and the confined geometry greatly affect configuration of the chains, segmental mobility and thermal transitions in the polymer thin films. In the semi-crystalline polymer thin films, the degree of crystallinity, crystallization dynamics, crystal morphology and lamellar orientation are different from their bulk counterparts. In this dissertation, a comprehensive study in the crystallization and melting of spun-coated thin and ultra-thin films of polyethylene-vinyl acetate)(EVA), linear low and medium density polyethylene (LLDPE and LMDPE) on selected substrates was made. The morphology, the lamellar orientation and the melting point of the films were found to have strong dependence on the film thickness and the substrate. On the strongly attractive substrate such as silicon, the film crystallized as spherulite with densely organized edge-on lamellae for the films thicker than 100nm, the lamellae packed more loosely as the film thickness decreased, until finally exhibited a dense branching morphology with mainly flat-on lamellae when the film is thinner than 15nm. A large degree of crystallinity was observed in the film as thin as 15nm. On the less absorbent substrate such as polyimide, the films crystallized in a randomly organized lamellae structure, which showed little dependence on the film thickness. On all the substrates, the melting point of the film decreased with the film thickness decrease when the film was thinner than a critical thickness, the value of which varied for different substrates. The biggest Tm depression observed was between 12°C and 38°C, depending on the substrates. The finite size effect and the reduced melting entropy caused by the confined movement of the polymer chains due to the substrate absorption were suggested to be the main reasons for the sharp Tm depression. The chain orientation inside the crystals was measured by near edge X-ray absorption fine structure (NEXAFS) spectroscopy, which showed that on the silicon substrate, the chains oriented parallel to the substrate with b axis in the radiation direction of the fibrils of the spherulite, a axis perpendicular to the film surface.

  1. Wrinkle motifs in thin films

    PubMed Central

    Budrikis, Zoe; Sellerio, Alessandro L.; Bertalan, Zsolt; Zapperi, Stefano

    2015-01-01

    On length scales from nanometres to metres, partial adhesion of thin films with substrates generates a fascinating variety of patterns, such as ‘telephone cord’ buckles, wrinkles, and labyrinth domains. Although these patterns are part of everyday experience and are important in industry, they are not completely understood. Here, we report simulation studies of a previously-overlooked phenomenon in which pairs of wrinkles form avoiding pairs, focusing on the case of graphene over patterned substrates. By nucleating and growing wrinkles in a controlled way, we characterize how their morphology is determined by stress fields in the sheet and friction with the substrate. Our simulations uncover the generic behaviour of avoiding wrinkle pairs that should be valid at all scales. PMID:25758174

  2. VUV thin films, chapter 7

    NASA Technical Reports Server (NTRS)

    Zukic, Muamer; Torr, Douglas G.

    1993-01-01

    The application of thin film technology to the vacuum ultraviolet (VUV) wavelength region from 120 nm to 230 nm has not been fully exploited in the past because of absorption effects which complicate the accurate determination of the optical functions of dielectric materials. The problem therefore reduces to that of determining the real and imaginary parts of a complex optical function, namely the frequency dependent refractive index n and extinction coefficient k. We discuss techniques for the inverse retrieval of n and k for dielectric materials at VUV wavelengths from measurements of their reflectance and transmittance. Suitable substrate and film materials are identified for application in the VUV. Such applications include coatings for the fabrication of narrow and broadband filters and beamsplitters. The availability of such devices open the VUV regime to high resolution photometry, interferometry and polarimetry both for space based and laboratory applications. This chapter deals with the optics of absorbing multilayers, the determination of the optical functions for several useful materials, and the design of VUV multilayer stacks as applied to the design of narrow and broadband reflection and transmission filters and beamsplitters. Experimental techniques are discussed briefly, and several examples of the optical functions derived for selected materials are presented.

  3. Thin-film rechargeable lithium batteries

    SciTech Connect

    Dudney, N.J.; Bates, J.B.; Lubben, D.

    1994-11-01

    Small thin-film rechargeable cells have been fabricated with a lithium phosphorus oxyniuide electrolyte, Li metal anode, and Li{sub 1-x}Mn{sub 2}O{sub 4} as the cathode film. The cathode films were fabricated by several different techniques resulting in both crystalline and amorphous films. These were compared by observing the cell discharge behavior. Estimates have been made for the scale-up of such a thin-film battery to meet the specifications for the electric vehicle application. The specific energy, energy density, and cycle life are expected to meet the USABC mid-term criteria. However, the areas of the thin-films needed to fabricate such a cell are very large. The required areas could be greatly reduced by operating the battery at temperatures near 100{degrees}C or by enhancing the lithium ion transport rate in the cathode material.

  4. Plasmonic modes in thin films: quo vadis?

    NASA Astrophysics Data System (ADS)

    Politano, Antonio; Chiarello, Gennaro

    2014-07-01

    Herein, we discuss the status and the prospect of plasmonic modes in thin films. Plasmons are collective longitudinal modes of charge fluctuation in metal samples excited by an external electric field. Surface plasmons (SPs) are waves that propagate along the surface of a conductor with applications in magneto-optic data storage, optics, microscopy, and catalysis. In thin films the electronic response is influenced by electron quantum confinement. Confined electrons modify the dynamical screening processes at the film/substrate interface by introducing novel properties with potential applications and, moreover, they affect both the dispersion relation of SP frequency and the damping processes of the SP. Recent calculations indicate the emergence of acoustic surface plasmons (ASP) in Ag thin films exhibiting quantum well states and in graphene films. The slope of the dispersion of ASP decreases with film thickness. We also discuss open issues in research on plasmonic modes in graphene/metal interfaes.

  5. Magnetic thin films for information storage

    NASA Astrophysics Data System (ADS)

    Gau, George J.-S.

    1990-02-01

    In most storage technologies, the two critical components are the recording head and the recording medium; hence, improvements in storage media go hand in hand with improvements in read/write head technology. Thin films are becoming the dominant medium chosen to meet the burgeoning demand for information storage, and thin-film technology has been transferred to the read/write heads as well. Materials science plays an important role in correlating the structure, properties and processing of thin-film magnetic materials for both applications.

  6. Macro stress mapping on thin film buckling

    SciTech Connect

    Goudeau, P.; Villain, P.; Renault, P.-O.; Tamura, N.; Celestre, R.S.; Padmore, H.A.

    2002-11-06

    Thin films deposited by Physical Vapour Deposition techniques on substrates generally exhibit large residual stresses which may be responsible of thin film buckling in the case of compressive stresses. Since the 80's, a lot of theoretical work has been done to develop mechanical models but only a few experimental work has been done on this subject to support these theoretical approaches and nothing concerning local stress measurement mainly because of the small dimension of the buckling (few 10th mm). This paper deals with the application of micro beam X-ray diffraction available on synchrotron radiation sources for stress mapping analysis of gold thin film buckling.

  7. Broadband Characterization of Multiferroic Thin-Films

    NASA Astrophysics Data System (ADS)

    Orloff, Nathan; Mateu, Jordi; Murakami, Makoto; Takeuchi, Ichiro; Booth, James

    2007-03-01

    The electromagnetic response of ferroelectric and multiferroic thin films at microwave frequencies is important for a fundamental understanding of these materials, as well for potential applications in electronics and communications systems. We explore the high-frequency response (to 40 GHz) of dielectric thin-film samples using a distributed measurement technique that utilizes patterned transmission line devices. We combine these measurements with measurements of lumped-element capacitors at lower frequencies (100 Hz - 100 MHz) to obtain true broadband measurements (100 Hz - 40 GHz) of the complex permittivity of thin film samples as a function of temperature, and electric- or magnetic-field bias.

  8. Permanent laser conditioning of thin film optical materials

    DOEpatents

    Wolfe, C. Robert (Palo Alto, CA); Kozlowski, Mark R. (Pleasanton, CA); Campbell, John H. (Livermore, CA); Staggs, Michael (Tracy, CA); Rainer, Frank (Livermore, CA)

    1995-01-01

    The invention comprises a method for producing optical thin films with a high laser damage threshold and the resulting thin films. The laser damage threshold of the thin films is permanently increased by irradiating the thin films with a fluence below an unconditioned laser damage threshold.

  9. Spin hall effect in paramagnetic thin films

    E-print Network

    Xu, Huachun

    2009-05-15

    .................................................................. 24 2.3 Pattern transferring.............................................................................. 33 2.4 Thin film deposition ............................................................................ 34 2.5 Electroplating... fabrication............................................... 65 4.2.2 The second step electron beam lithography patterning.............. 69 4.2.3 Electroplating ............................................................................. 78 V MEASUREMENT...

  10. Thermally tunable ferroelectric thin film photonic crystals.

    SciTech Connect

    Lin, P. T.; Wessels, B. W.; Imre, A.; Ocola, L. E.; Northwestern Univ.

    2008-01-01

    Thermally tunable PhCs are fabricated from ferroelectric thin films. Photonic band structure and temperature dependent diffraction are calculated by FDTD. 50% intensity modulation is demonstrated experimentally. This device has potential in active ultra-compact optical circuits.

  11. Visible spectrometer utilizing organic thin film absorption

    E-print Network

    Tiefenbruck, Laura C. (Laura Christine)

    2004-01-01

    In this thesis, I modeled and developed a spectrometer for the visible wavelength spectrum, based on absorption characteristics of organic thin films. The device uses fundamental principles of linear algebra to reconstruct ...

  12. Thin film production method and apparatus

    DOEpatents

    Loutfy, Raouf O. (Tucson, AZ); Moravsky, Alexander P. (Tucson, AZ); Hassen, Charles N. (Tucson, AZ)

    2010-08-10

    A method for forming a thin film material which comprises depositing solid particles from a flowing suspension or aerosol onto a filter and next adhering the solid particles to a second substrate using an adhesive.

  13. Thin-film reliability and engineering overview

    NASA Technical Reports Server (NTRS)

    Ross, R. G., Jr.

    1984-01-01

    The reliability and engineering technology base required for thin film solar energy conversions modules is discussed. The emphasis is on the integration of amorphous silicon cells into power modules. The effort is being coordinated with SERI's thin film cell research activities as part of DOE's Amorphous Silicon Program. Program concentration is on temperature humidity reliability research, glass breaking strength research, point defect system analysis, hot spot heating assessment, and electrical measurements technology.

  14. Sculptured thin films — II. Experiments and applications

    Microsoft Academic Search

    R. Messier; Akhlesh Lakhtakia

    1999-01-01

    A report on the preparation and potential applications of sculptured thin films (STFs) is presented. STFs are nano-engineered\\u000a columnar thin films in which the columnar direction can made to change easily and often during growth. STFs of virtually any\\u000a material can be prepared through directional vapor deposition onto any surface under low adatom-mobility conditions. Columnar\\u000a shapes, such as zig-zag, C-,

  15. Thin solid-lubricant films in space

    NASA Astrophysics Data System (ADS)

    Roberts, E. W.

    Low-friction films of thickness as low as 1 micron, created through sputter-deposition of low shear strength materials, are required in spacecraft applications requiring low power dissipation, such as cryogenic devices, and low torque noise, such as precision-pointing mechanisms. Due to their thinness, these coatings can be applied to high precision-machined tribological components without compromising their functional accuracy. Attention is here given to the cases of thin solid films for ball bearings, gears, and journal bearings.

  16. Microelectromechanical systems based on ferroelectric thin films

    Microsoft Academic Search

    Dennis L. Polla

    1995-01-01

    Ferroelectric thin films have been integrated in silicon-based microelectromechanical systems, commonly called MEMS. Several thin films of the PZT family have been used in the formation of both microsensors and microactuators in processes compatible with 2-?m analog CMOS technology. Ferroelectric MEMS offer significant advantages of high signal-to-noise, low power dissipation, and high force generation in comparison to other MEMS technologies

  17. Advances in CZTS thin films and nanostructured

    NASA Astrophysics Data System (ADS)

    Ali, N.; Ahmed, R.; Bakhtiar-Ul-Haq; Shaari, A.

    2015-06-01

    Already published data for the optical band gap (Eg) of thin films and nanostructured copper zinc tin sulphide (CZTS) have been reviewed and combined. The vacuum (physical) and non-vacuum (chemical) processes are focused in the study for band gap comparison. The results are accumulated for thin films and nanostructured in different tables. It is inferred from the re- view that the nanostructured material has plenty of worth by engineering the band gap for capturing the maximum photons from solar spectrum.

  18. Growth and Properties of SmFeAsO1-xFx thin films using pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Lee, Sanghan; Folkman, Chad; Hyub Baek, Seung; Felker, David; Rzchowski, Mark; Eom, Chang Beom; Jiang, Jianyi; Hellstrom, Eric

    2009-03-01

    The discovery of iron pnictide superconductors has been gaining interest due to their highest transition temperatures (Tc) among transition metal compound except cuprate systems. In iron pnictide system, Tc has been significantly enhanced by replacing elements. The growth of epitaxial thin film of this interesting compound is desirable for fundamental understanding of superconductivity and potential device applications. So far, there is no report with successful growth of epitaxial thin films with the same Tc of the bulk materials. Although several reports show Tc of thin film, the resistivity dose not reach zero down to at 4K. We have employed pulsed laser deposition for the growth of iron pnictides, SmFeAsO1-xFx, thin films on various single crystal substrates followed by ex--situ post annealing. In this talk, we will discuss the structural and superconducting properties of SmFeAsO1-xFx thin film including Tc, Jc and Hc2.

  19. Combinatorial Arc Plasma Deposition of Thin Films

    NASA Astrophysics Data System (ADS)

    Hata, Seiichi; Yamauchi, Ryusuke; Sakurai, Junpei; Shimokohbe, Akira

    2006-04-01

    In this paper, we introduce a new combinatorial thin film deposition process that uses arc plasma [combinatorial arc plasma deposition (CAPD)]. The major goal of CAPD in this study is to search for new compositions of amorphous thin film alloys. CAPD uses three cathodic arc plasma guns and the guns shoot the pulse like plasma one by one at a specific time interval. The plasma from each gun is guided onto a substrate by a magnetic field at a specific area on the substrate so as to deposit a compositionally-graded thin film. The deposited thin film is separated into 1,089 samples (the size of each is 1 × 1 mm2) by a trench grid on the substrate. The samples together are called the thin film library and all samples are numbered by the 5-bit row and column marks in the grid. To prove CAPD, a thin film library of a Pd-Cu-Si alloy system was deposited. The composition and non crystallinity of 180 samples were evaluated using energy-dispersive X-ray fluorescence spectrometer (EDX) and imaging-plate X-ray diffractometer (IP-XRD), respectively. Both measurements were performed without detaching the samples from the library. Analysis of 180 samples showed a graded composition, and some of the samples were shown to be amorphous.

  20. Thin films, asphaltenes, and reservoir wettability

    SciTech Connect

    Kaminsky, R.; Bergeron, V.; Radke, C.J. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., Berkeley, CA (United States). Dept. of Chemical Engineering

    1993-04-01

    Reservoir wettability impacts the success of oil recovery by waterflooding and other methods. To understand wettability and its alteration, thin-film forces in solid-aqueous-oil systems must be elucidated. Upon rupture of thick aqueous films separating the oil and rock phases, asphaltene components in the crude oil adsorb irreversibly on the solid surface, changing it from water-wet to oil-wet. Conditions of wettability alteration can be found by performing adhesion tests, in which an oil droplet is brought into contact with a solid surface. Exceeding a critical capillary pressure destabilizes the film, causing spontaneous film rupture to a molecularly adsorbed layer and oil adhesion accompanied by pinning at the three-phase contact line. The authors conduct adhesion experiments similar to those of Buckley and Morrow and simultaneously examine the state of the underlying thin film using optical microscopy and microinterferometry. Aqueous thin films between an asphaltic Orcutt crude oil and glass surfaces are studied as a function of aqueous pH and salinity. For the first time, they prove experimentally that strongly water-wet to strongly oil-wet wettability alteration and contact-angle pinning occur when thick aqueous films thin to molecularly adsorbed films and when the oil phase contains asphaltene molecules.

  1. Current induced effects in aluminum thin films

    Microsoft Academic Search

    A. i. Oliva; P. Quintanasupasu; O. Ceh; J. e. Corona; M. Aguilar

    1999-01-01

    Aluminum thin films grown on silicon by free evaporation were studied by grazing incidence X-ray diffraction and atomic force microscopy techniques. The behavior of the films during current flowing, the induced changes by large periods of current applied, as well as the temporal evolution of the deformation due to thermal expansion because of the Joule effect, were studied. We explain

  2. Surface Plasmons in Thin Metallic Films

    E-print Network

    A. V. Latyshev; A. A. Yushkanov

    2010-10-11

    For the first time it is shown that for thin metallic films thickness of which not exceed thickness of skin -- layer, the problem of description of surface plasma oscillations allows analytical solution by arbitrary ratio between length of electrons free path and thickness of a film. The dependance of frequency surface plasma oscillations on wave number is carry out.

  3. Thin transparent films formed from powdered glass

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Glass film less than five mils thick is formed from powdered glass dispersed in an organic liquid, deposited on a substrate, and fused into place. The thin films can be cut and shaped for contact lenses, optical filters and insulating layers.

  4. Thin film magnetic materials for RFIC passives

    Microsoft Academic Search

    Y. Zhuang; M. Vroubel; B. Rejaei; J. N. Burghartz

    2005-01-01

    Recent developments of magnetic thin films for monolithic integrated radio frequency (RF) passive components are reviewed. Challenges of applying magnetic films for RF devices, i.e. ferromagnetic resonance (FMR) and eddy current effects are discussed. Nano-granular magnetic materials are foreseen to be one of the most suitable candidate materials for RFIC for the low eddy current losses and the high FMR.

  5. Biaxial Fatigue Testing of Thin Films

    Microsoft Academic Search

    S. Eve; N. Huber; E. Ernst; A. Last; M. Schlagenhof; O. Kraff

    2006-01-01

    A new experimental setup, which allows for testing in an equi-biaxial loading condition, has been developed and applied to investigate the fatigue behaviour of thin films. A load controlled cycling, performed at room temperature on flat specimens, reproduces the strain amplitude and mean strain in the film corresponding to a thermal cycling in a given temperature range. The setup is

  6. Formation of thin film Tl-based high-Tc? superconducting oxides from amorphous alloy precursors 

    E-print Network

    Williams, John Charles

    1991-01-01

    -based thin film superconductors. The most popular deposition method seems to be through the use of sputter techniques. IS SO 31 32 33 Sputter deposition methods have been used to produce nearly single-phase 2212 films with a T, near 100 K1s 3o 3~ 32 ss... highly oriented 2021 and 2212 phase films. 4S 44 Hermann et aL reports using two different techniques. 4s One technique uses either magnetron sputtering or laser ablation of Ba-Ca-Cu oxides onto various substrates. Thallium vapor diffusion...

  7. Thin monocrystalline silicon films for solar cells

    Microsoft Academic Search

    C. S. Solanki; R. R. Bilyalov; G. Beaucarne; J. Poortmans

    2003-01-01

    Thin film monocrystalline silicon solar cells based on porous silicon layer transfer processes could be cost-effective because of their lower consumption of material use and the potential for high efficiency. Novel techniques of porous silicon film separation, obtained by anodization of silicon, are presented. Anodization techniques for porous silicon film separation are classified as either one-step or two-step. Two-step anodization

  8. Microcrystalline organic thin-film solar cells.

    PubMed

    Verreet, Bregt; Heremans, Paul; Stesmans, Andre; Rand, Barry P

    2013-10-11

    Microcrystalline organic films with tunable thickness are produced directly on an indium-tin-oxide substrate, by crystallizing a thin amorphous rubrene film followed by its use as a template for subsequent homoepitaxial growth. These films, with exciton diffusion lengths exceeding 200 nm, produce solar cells with increasing photocurrents at thicknesses up to 400 nm with a fill factor >65%, demonstrating significant potential for microcrystalline organic electronic devices. PMID:23939936

  9. Annealing behavior of electroplated permalloy thin films

    Microsoft Academic Search

    R. L. Anderson; A. Gangulee; L. T. Romankiw

    1973-01-01

    The isochronal annealing behavior of electroplated 1.2 ?m Ni-Fe thin films containing nominally 80 wt% Ni, in the temperature\\u000a range from 373? to 773?K, and with a magnetic field parallel to the easy axis of the films, was investigated through measurements\\u000a of the films’ structural, magnetic and electrical properties. The effects of annealing could be described in terms of two

  10. Annealing behavior of electroplated permalloy thin films

    Microsoft Academic Search

    R. L. Anderson; A. Gangulee; L. T. Romankiw

    1973-01-01

    The isochronal annealing behavior of electroplated 1.2 µm Ni-Fe thin films containing nominally 80 wt% Ni, in the temperature range from 373° to 773°K, and with a magnetic field parallel to the easy axis of the films, was investigated through measurements of the films' structural, magnetic and electrical properties. The effects of annealing could be described in terms of two

  11. Chalcopyrite thin film solar cells by electrodeposition

    Microsoft Academic Search

    D. Lincot; J. F. Guillemoles; S. Taunier; D. Guimard; J. Sicx-Kurdi; A. Chaumont; O. Roussel; O. Ramdani; C. Hubert; J. P. Fauvarque; N. Bodereau; L. Parissi; P. Panheleux; P. Fanouillere; N. Naghavi; P. P. Grand; M. Benfarah; P. Mogensen; O. Kerrec

    2004-01-01

    This paper reviews the state of the art in using electrodeposition to prepare chalcopyrite absorber layers in thin film solar cells. Most of the studies deal with the direct preparation of Cu(In,Ga)Se2 films, and show that the introduction of gallium in the films is now becoming possible from single bath containing all the elements. Electrodeposition can also be used to

  12. Polysilicon Super-Thin-Film Transistor (SFT)

    Microsoft Academic Search

    Hisao Hayashi; Takashi Noguchi; Takefumi Oshima

    1984-01-01

    N-channel MOS FET's have been fabricated in super-thin polysilicon film on quartz substrate. The thickness of the film had an important role in improving the electrical properties. Moreover, grain boundary passivation by the hydrogen from a plasma-SiN film has been developed to increase the field effect mobility. The field effect mobility is more than 20 cm2\\/V\\\\cdots at the polysilicon thickness

  13. Preparation and Properties of Thin Ferrite Films

    Microsoft Academic Search

    E. Banks; N. H. Riederman; H. W. Schleuning; L. M. Silber

    1961-01-01

    Thin films of ferrites, of the order of 1000 A thickness, have been prepared by vacuum evaporation of the metals, and subsequent high-temperature oxidation. Films of iron, nickel, cobalt, magnesium, and copper ferrites, mixed ferrites, and mixed ferrite-aluminates, as well as yttrium iron garnet, have been prepared. X-ray powder diffractometry indicates that the ferrite films are single-phase spinels, while the

  14. Study of iron mononitride thin films

    SciTech Connect

    Tayal, Akhil, E-mail: mgupta@csr.res.in; Gupta, Mukul, E-mail: mgupta@csr.res.in; Phase, D. M., E-mail: mgupta@csr.res.in; Reddy, V. R., E-mail: mgupta@csr.res.in; Gupta, Ajay, E-mail: mgupta@csr.res.in [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore,-452001 (India)

    2014-04-24

    In this work we have studied the crystal structural and local ordering of iron and nitrogen in iron mononitride thin films prepared using dc magnetron sputtering at sputtering power of 100W and 500W. The films were sputtered using pure nitrogen to enhance the reactivity of nitrogen with iron. The x-ray diffraction (XRD), conversion electron Mössbauer spectroscopy (CEMS) and soft x-ray absorption spectroscopy (SXAS) studies shows that the film crystallizes in ZnS-type crystal structure.

  15. RF surface resistance of YBa2Cu3O(7-x) thin films

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The excitement engendered by the discovery of the new T sub c oxide superconductors has led to much speculation about practical applications of thin films of these materials in digital and analog electronic devices. Most of these envisioned applications involve high frequency signals for which a detailed knowledge of the surface impedance of the novel superconductors is very important. We have measured the surface resistance of thin films of YBaCuO in the frequency range 0.5 less than f less than 17 GHz using a stripline-resonator method. The stripline procedure also was used to measure the surface resistance of high quality gold and aluminum films; the resistance values obtained agree with values predicted from the measured dc resistance using the Pippard formalism for the anomalous skin effect. The YBaCuO were produced by a multilayer deposition process. The films are formed by e-beam evaporation of 24 layers of Y, Ba, and Cu. Films with the highest transition temperature were obtained using yttria-stabilized zirconia (YSZ) substrates. After deposition, the films are transferred to a furnace where they are annealed in flowing O2 at 850 C for 2h. The furnace then is turned off and allowed to cool to 100 C in about 16 h. Auger profiling of the films made by this process shows that the concentrations of Y, Ba, Cu, and O are uniform to within 1 percent throughout the thickness of the film.

  16. Thin-film rechargeable lithium batteries

    SciTech Connect

    Dudney, N.J.; Bates, J.B.; Lubben, D. [Oak Ridge National Lab., TN (United States). Solid State Div.

    1995-06-01

    Thin-film rechargeable lithium batteries using ceramic electrolyte and cathode materials have been fabricated by physical deposition techniques. The lithium phosphorous oxynitride electrolyte has exceptional electrochemical stability and a good lithium conductivity. The lithium insertion reaction of several different intercalation materials, amorphous V{sub 2}O{sub 5}, amorphous LiMn{sub 2}O{sub 4}, and crystalline LiMn{sub 2}O{sub 4} films, have been investigated using the completed cathode/electrolyte/lithium thin-film battery.

  17. Thin film absorber for a solar collector

    DOEpatents

    Wilhelm, William G. (Cutchogue, NY)

    1985-01-01

    This invention pertains to energy absorbers for solar collectors, and more particularly to high performance thin film absorbers. The solar collectors comprising the absorber of this invention overcome several problems seen in current systems, such as excessive hardware, high cost and unreliability. In the preferred form, the apparatus features a substantially rigid planar frame with a thin film window bonded to one planar side of the frame. An absorber in accordance with the present invention is comprised of two thin film layers that are sealed perimetrically. In a preferred embodiment, thin film layers are formed from a metal/plastic laminate. The layers define a fluid-tight planar envelope of large surface area to volume through which a heat transfer fluid flows. The absorber is bonded to the other planar side of the frame. The thin film construction of the absorber assures substantially full envelope wetting and thus good efficiency. The window and absorber films stress the frame adding to the overall strength of the collector.

  18. Finite deformation mechanics in buckled thin films on compliant supports

    E-print Network

    Rogers, John A.

    Finite deformation mechanics in buckled thin films on compliant supports Hanqing Jiang*, Dahl experimental and theoretical studies of the mechanics of thin buckled films on compliant substrates. In par, and others. buckling stiff thin film compliant substrate stretchable electronics Nonlinear buckling of thin

  19. Nanostructured thin films as functional coatings

    NASA Astrophysics Data System (ADS)

    Lazar, Manoj A.; Tadvani, Jalil K.; Sze Tung, Wing; Lopez, Lorena; Daoud, Walid A.

    2010-06-01

    Nanostructured thin films is one of the highly exploiting research areas particularly in applications such as photovoltaics, photocatalysis and sensor technologies. Highly tuned thin films, in terms of thickness, crystallinity, porosity and optical properties, can be fabricated on different substrates using the sol-gel method, chemical solution deposition (CSD), electrochemical etching, along with other conventional methods such as chemical vapour deposition (CVD) and physical vapour deposition (PVD). The above mentioned properties of these films are usually characterised using surface analysis techniques such as XRD, SEM, TEM, AFM, ellipsometry, electrochemistry, SAXS, reflectance spectroscopy, STM, XPS, SIMS, ESCA, X-ray topography and DOSY-NMR. This article presents a short review of the preparation and characterisation of thin films of nanocrystalline titanium dioxide and modified silicon as well as their application in solar cells, water treatment, water splitting, self cleaning fabrics, sensors, optoelectronic devices and lab on chip systems.

  20. LPG sensing performance of nanostructured zinc oxide thin films

    NASA Astrophysics Data System (ADS)

    Bari, A. R.; Patil, L. A.

    2013-06-01

    Nanostructured zinc oxide thin films were prepared using ultrasonic spray pyrolysis technique. Zinc acetate was used as a starting precursor. As prepared thin films were characterized using different analytical techniques. The sensing performance of the nanostructured zinc oxide thin films was studied on exposure of various gases. The films were observed to be most sensitive (S= 1727) to LPG at 300°C.

  1. BZN THIN FILM CAPACITORS FOR MICROWAVE LOW LOSS TUNABLE APPLICATIONS

    E-print Network

    York, Robert A.

    was fabricated on platinized vycor glass substrate. BZN film is prepared by RF magnetron sputtering system afterBZN THIN FILM CAPACITORS FOR MICROWAVE LOW LOSS TUNABLE APPLICATIONS Jaehoon Park, Jiwei Lu candidates so far is BST thin film. However, the strong function of thin film thickness is its permittivity

  2. NANO-INDENTATION OF COPPER THIN FILMS ON SILICON SUBSTRATES

    E-print Network

    Suresh, Subra

    NANO-INDENTATION OF COPPER THIN FILMS ON SILICON SUBSTRATES S. Suresh1 , T.-G. Nieh2 and B.W. Choi2: Mechanical properties; Nano-indentation; Thin films; Copper; Dislocations Introduction Indentation methods films on substrates (e.g., [2,3]) using instrumented indentation. Nano-indentation studies of thin films

  3. MOF thin films: existing and future applications.

    PubMed

    Shekhah, O; Liu, J; Fischer, R A; Wöll, Ch

    2011-02-01

    The applications and potentials of thin film coatings of metal-organic frameworks (MOFs) supported on various substrates are discussed in this critical review. Because the demand for fabricating such porous coatings is rather obvious, in the past years several synthesis schemes have been developed for the preparation of thin porous MOF films. Interestingly, although this is an emerging field seeing a rapid development a number of different applications on MOF films were either already demonstrated or have been proposed. This review focuses on the fabrication of continuous, thin porous films, either supported on solid substrates or as free-standing membranes. The availability of such two-dimensional types of porous coatings opened the door for a number of new perspectives for functionalizing surfaces. Also for the porous materials themselves, the availability of a solid support to which the MOF-films are rigidly (in a mechanical sense) anchored provides access to applications not available for the typical MOF powders with particle sizes of a few ?m. We will also address some of the potential and applications of thin films in different fields like luminescence, QCM-based sensors, optoelectronics, gas separation and catalysis. A separate chapter has been devoted to the delamination of MOF thin films and discusses the potential to use them as free-standing membranes or as nano-containers. The review also demonstrates the possibility of using MOF thin films as model systems for detailed studies on MOF-related phenomena, e.g. adsorption and diffusion of small molecules into MOFs as well as the formation mechanism of MOFs (101 references). PMID:21225034

  4. Wear resistance of iron oxide thin films

    NASA Astrophysics Data System (ADS)

    Chen, Mao-Min; Lin, Judy; Wu, Tsai-Wei; Castillo, Gilbert

    1988-04-01

    Magnetite films (Fe3O4) were reactively sputtered onto (100) silicon substrates in an Ar+O2 gas environment from a target containing Fe and 0.75 at. % Os. The films were then oxidized in air to form ?-Fe2O3. The wear resistance of the films was evaluated using an oscillatory wear tester and a contact start/stop tester with IBM 3380 type of sliders. Magnetite films exhibited poor durability independent of the deposition substrate temperature and oxygen partial pressure. Upon oxidizing the magnetite films in air at elevated temperatures, the wear resistance increased. For fixed deposition conditions, the wear resistance of the film increased with oxidation temperature. However, too high an oxidation temperature will transform the film into ?-Fe2O3, which is antiferromagnetic material. For a fixed oxidation temperature of 300 °C, the wear resistance of the film increased with increasing deposition substrate temperature. Durable ?-Fe2O3 thin film can be produced by depositing 1000-Å-thick film at 325 °C and subsequently oxidizing the film at 300 °C. A visible wear track was detected only after 16 000 contact start/stop cycles for ?-Fe2O3 film media without additional layers of overcoat or lubricant in ambient environment. The friction coefficient was low and remained stable with sliding cycles. The dependence of friction coefficient of the film on deposition conditions will be discussed.

  5. Sprayed lanthanum doped zinc oxide thin films

    NASA Astrophysics Data System (ADS)

    Bouznit, Y.; Beggah, Y.; Ynineb, F.

    2012-01-01

    Lanthanum doped zinc oxide thin films were deposited on soda-lime glass substrates using a pneumatic spray pyrolysis technique. The films were prepared using different lanthanum concentrations at optimum deposition parameters. We studied the variations in structural, morphological and optical properties of the samples due to the change of doping concentration in precursor solutions. X-ray diffraction (XRD) patterns show that pure and La-doped ZnO thin films are highly textured along c-axis perpendicular to the surface of the substrate. Scanning electron micrographs show that surface morphology of ZnO films undergoes a significant change according to lanthanum doping. All films exhibit a transmittance higher than 80% in the visible region.

  6. AC impedance analysis of polypyrrole thin films

    NASA Technical Reports Server (NTRS)

    Penner, Reginald M.; Martin, Charles R.

    1987-01-01

    The AC impedance spectra of thin polypyrrole films were obtained at open circuit potentials from -0.4 to 0.4 V vs SCE. Two limiting cases are discussed for which simplified equivalent circuits are applicable. At very positive potentials, the predominantly nonfaradaic AC impedance of polypyrrole is very similar to that observed previously for finite porous metallic films. Modeling of the data with the appropriate equivalent circuit permits effective pore diameter and pore number densities of the oxidized film to be estimated. At potentials from -0.4 to -0.3 V, the polypyrrole film is essentially nonelectronically conductive and diffusion of polymer oxidized sites with their associated counterions can be assumed to be linear from the film/substrate electrode interface. The equivalent circuit for the polypyrrole film at these potentials is that previously described for metal oxide, lithium intercalation thin films. Using this model, counterion diffusion coefficients are determined for both semi-infinite and finite diffusion domains. In addition, the limiting low frequency resistance and capacitance of the polypyrrole thin fims was determined and compared to that obtained previously for thicker films of the polymer. The origin of the observed potential dependence of these low frequency circuit components is discussed.

  7. Self-organized superconducting textures in thin films.

    SciTech Connect

    Glatz, A.; Aranson, I.; Vinokur, V. M.; Chtchelkatchev, N. M.; Baturina, T. I. (Materials Science Division); (Russian Academy of Sciences); (Moscow Inst. of Physics and Technology); (Inst. Semiconductor Physics); (Novosibirsk State Univ.)

    2011-07-07

    The interplay between the superconducting order parameter and elastic fields, which are intimately connected to the very existence of the superconductivity itself, can result in a novel superconducting state: a regular self-organized texture of superconducting islands. We study the formation of these islands in a system of a thin superconducting film coupled elastically to a more rigid substrate and derive the phase diagram below the superconducting critical temperature depending on the elastic coupling constant of both subsystems. The fact that this pattern is a result of the Ginzburg-Landau description of superconductivity indicates that the formation of regular structures may be a common feature of the superconductor transition in the presence of long-range coupling.

  8. Crossover from 2D to 3D behavior in the superfluid density of thin YBa2Cu3O7d films

    E-print Network

    Crossover from 2D to 3D behavior in the superfluid density of thin YBa2Cu3O7Àd films Yuri L. Zuev aS(T) at a temperature consistent with a 2D vortex-pair unbinding transition. In this paper, we show that this characteristic feature of 2D superconductors diminishes with increasing film thickness consistent with theory

  9. A high performance thin film thermoelectric cooler

    SciTech Connect

    Rowe, D.M.; Min, G.; Volklein, F.

    1998-07-01

    Thin film thermoelectric devices with small dimensions have been fabricated using microelectronics technology and operated successfully in the Seebeck mode as sensors or generators. However, they do not operate successfully in the Peltier mode as coolers, because of the thermal bypass provided by the relatively thick substrate upon which the thermoelectric device is fabricated. In this paper a processing sequence is described which dramatically reduces this thermal bypass and facilitates the fabrication of high performance integrated thin film thermoelectric coolers. In the processing sequence a very thin amorphous SiC (or SiO{sub 2}SiN{sub 4}) film is deposited on a silicon substrate using conventional thin film deposition and a membrane formed by removing the silicon substrate over a desired region using chemical etching or micro-machining. Thermoelements are deposited on the membrane using conventional thin film deposition and patterning techniques and configured so that the region which is to be cooled is abutted to the cold junctions of the Peltier thermoelements while the hot junctions are located at the outer peripheral area which rests on the silicon substrate rim. Heat is pumped laterally from the cooled region to the silicon substrate rim and then dissipated vertically through it to an external heat sink. Theoretical calculations of the performance of a cooler described above indicate that a maximum temperature difference of about 40--50K can be achieved with a maximum heat pumping capacity of around 10 milliwatts.

  10. Thermal fatigue testing of thin metal films

    NASA Astrophysics Data System (ADS)

    Mönig, R.; Keller, R. R.; Volkert, C. A.

    2004-11-01

    An experimental method is described for performing thermal fatigue testing of thin films and lines on substrates. The method uses Joule heating from alternating currents to generate temperature, strain, and stress cycles in the metal structures. The apparatus has been installed in a scanning electron microscope and allows in situ observations of the fatigue damage evolution. First observations on Cu films reveal that fatigue damage forms in submicrometer thick films and is strongly affected by the film thickness and grain size. In addition, results from a special test structure confirm that the damage is caused by fatigue and not by electromigration.

  11. Flow factor approach to molecularly thin hydrodynamic film lubrication

    Microsoft Academic Search

    Yongbin Zhang

    2006-01-01

    Molecularly thin hydrodynamic film lubrication is the mode of lubrication where the lubricating film is molecularly thin and the lubricating media across the film thickness is molecule instead of the conventional continuum lubricant material. In this lubrication, across the film thickness, the film is non-continuum due to its molecular thickness while the lubricating molecule is discretely distributed and its behavior

  12. Thin-film flows without precursors

    NASA Astrophysics Data System (ADS)

    Juanes, Ruben; Cueto-Felgueroso, Luis; Szulczewski, Michael

    2012-11-01

    The flow of thin films over flat surfaces has been the subject of much theoretical, experimental and computational research. Under the lubrication approximation, the classical mathematical model for these flows takes the form of a nonlinear fourth-order PDE, where the fourth-order term models the effect of surface tension. This classical model, however, effectively assumes that the film is perfectly wetting to the substrate and, therefore, does not capture the partial wetting regime. Partial wetting is responsible for stopping the spread of a liquid puddle, and for pinning the contact line of a viscous liquid down an incline, controlling the morphology of the fingering pattern that ensues. Here, we extend our recent work on macroscopic phase-field modeling of two-phase flow in a capillary tube to thin-film flows with partial wetting. Our model naturally accounts for the dynamic contact angle at the contact line, and therefore permits modeling thin-film flows without invoking a precursor film, leading to compactly-supported solutions. We model the statics and dynamics of a liquid puddle, and the fingering behavior of flow down an incline. We compare model predictions with experiments of thin-film flows both on a horizontal plane and down an incline, for different contact angles.

  13. Crystallization of zirconia based thin films.

    PubMed

    Stender, D; Frison, R; Conder, K; Rupp, J L M; Scherrer, B; Martynczuk, J M; Gauckler, L J; Schneider, C W; Lippert, T; Wokaun, A

    2015-07-01

    The crystallization kinetics of amorphous 3 and 8 mol% yttria stabilized zirconia (3YSZ and 8YSZ) thin films grown by pulsed laser deposition (PLD), spray pyrolysis and dc-magnetron sputtering are explored. The deposited films were heat treated up to 1000 °C ex situ and in situ in an X-ray diffractometer. A minimum temperature of 275 °C was determined at which as-deposited amorphous PLD grown 3YSZ films fully crystallize within five hours. Above 325 °C these films transform nearly instantaneously with a high degree of micro-strain when crystallized below 500 °C. In these films the t'' phase crystallizes which transforms at T > 600 °C to the t' phase upon relaxation of the micro-strain. Furthermore, the crystallization of 8YSZ thin films grown by PLD, spray pyrolysis and dc-sputtering are characterized by in situ XRD measurements. At a constant heating rate of 2.4 K min(-1) crystallization is accomplished after reaching 800 °C, while PLD grown thin films were completely crystallized already at ca. 300 °C. PMID:26119755

  14. Capillary stress in microporous thin films

    SciTech Connect

    Samuel, J.; Hurd, A.J.; Frink, L.J.D.; Swol, F. van [Sandia National Labs., Albuquerque, NM (United States); Brinker, C.J. [Sandia National Labs., Albuquerque, NM (United States). Ceramic Processing Science Dept.]|[Univ. of New Mexico, Albuquerque, NM (United States). Center for Micro Engineering Ceramics; Raman, N.K. [Univ. of New Mexico, Albuquerque, NM (United States). Center for Micro Engineered Ceramics

    1996-06-01

    Development of capillary stress in porous xerogels, although ubiquitous, has not been systematically studied. The authors have used the beam bending technique to measure stress isotherms of microporous thin films prepared by a sol-gel route. The thin films were prepared on deformable silicon substrates which were then placed in a vacuum system. The automated measurement was carried out by monitoring the deflection of a laser reflected off the substrate while changing the overlying relative pressure of various solvents. The magnitude of the macroscopic bending stress was found to reach a value of 180 MPa at a relative pressure of methanol, P/Po = 0.001. The observed stress is determined by the pore size distribution and is an order of magnitude smaller in mesoporous thin films. Density Functional Theory (DFT) indicates that for the microporous materials, the stress at saturation is compressive and drops as the relative pressure is reduced.

  15. Thin film thermal sensor fabrication and application

    NASA Astrophysics Data System (ADS)

    Gualous, Hamid

    1999-10-01

    This paper is about a gold palladium thin-film microthermocouple gate array. The gate array is fabricated by standard photolithography and sputtering technology. The sensor has been developed to characterize the energetic profile of laser power. The thermal sensor is a thin film thermocouple gate array with 16 sensing junctions per 288 micrometers . The response of Au/Pd thin-film thermocouple has been characterized, the time constant of thermocouple response is in order of 140 microsecond(s) . Furthermore, a linear graph giving the thermoelastic voltage versus the incident power laser has been obtained. Finally, the spot size and the intensity profile of laser beam have been estimated using the sensor.

  16. Thin film ferroelectric electro-optic memory

    NASA Technical Reports Server (NTRS)

    Thakoor, Sarita (Inventor); Thakoor, Anilkumar P. (Inventor)

    1993-01-01

    An electrically programmable, optically readable data or memory cell is configured from a thin film of ferroelectric material, such as PZT, sandwiched between a transparent top electrode and a bottom electrode. The output photoresponse, which may be a photocurrent or photo-emf, is a function of the product of the remanent polarization from a previously applied polarization voltage and the incident light intensity. The cell is useful for analog and digital data storage as well as opto-electric computing. The optical read operation is non-destructive of the remanent polarization. The cell provides a method for computing the product of stored data and incident optical data by applying an electrical signal to store data by polarizing the thin film ferroelectric material, and then applying an intensity modulated optical signal incident onto the thin film material to generate a photoresponse therein related to the product of the electrical and optical signals.

  17. Vibration welding system with thin film sensor

    DOEpatents

    Cai, Wayne W; Abell, Jeffrey A; Li, Xiaochun; Choi, Hongseok; Zhao, Jingzhou

    2014-03-18

    A vibration welding system includes an anvil, a welding horn, a thin film sensor, and a process controller. The anvil and horn include working surfaces that contact a work piece during the welding process. The sensor measures a control value at the working surface. The measured control value is transmitted to the controller, which controls the system in part using the measured control value. The thin film sensor may include a plurality of thermopiles and thermocouples which collectively measure temperature and heat flux at the working surface. A method includes providing a welder device with a slot adjacent to a working surface of the welder device, inserting the thin film sensor into the slot, and using the sensor to measure a control value at the working surface. A process controller then controls the vibration welding system in part using the measured control value.

  18. Thin film photovoltaics -- Strategy of Eurec Agency

    SciTech Connect

    Bloss, W.H. [Univ. Stuttgart (Germany). Inst. fuer Physikalische Elektronik

    1994-12-31

    European activities in the field of thin film photovoltaics are coordinated in a network by Eurec Agency (European Renewable Energy Centres Agency). Main emphasis lies in the development of an appropriate production technology of CIS and CdTe based photovoltaic modules in an industrial scale. These efforts are supported by a research program on relevant materials, structures and processes for thin film photovoltaics. Substantial progress has been achieved during the last years which opens new perspectives for future trends. Joint efforts in research and development based on CIS are coordinated by the network EUROCIS. A screening program on natural minerals with relevance to photovoltaic performance provides the basis for further strategic steps.

  19. Micro-sensor thin-film anemometer

    NASA Technical Reports Server (NTRS)

    Sheplak, Mark (Inventor); McGinley, Catherine B. (Inventor); Spina, Eric F. (Inventor); Stephens, Ralph M. (Inventor); Hopson, Jr., Purnell (Inventor); Cruz, Vincent B. (Inventor)

    1996-01-01

    A device for measuring turbulence in high-speed flows is provided which includes a micro-sensor thin-film probe. The probe is formed from a single crystal of aluminum oxide having a 14.degree. half-wedge shaped portion. The tip of the half-wedge is rounded and has a thin-film sensor attached along the stagnation line. The bottom surface of the half-wedge is tilted upward to relieve shock induced disturbances created by the curved tip of the half-wedge. The sensor is applied using a microphotolithography technique.

  20. Feasibility Study of Thin Film Thermocouple Piles

    NASA Technical Reports Server (NTRS)

    Sisk, R. C.

    2001-01-01

    Historically, thermopile detectors, generators, and refrigerators based on bulk materials have been used to measure temperature, generate power for spacecraft, and cool sensors for scientific investigations. New potential uses of small, low-power, thin film thermopiles are in the area of microelectromechanical systems since power requirements decrease as electrical and mechanical machines shrink in size. In this research activity, thin film thermopile devices are fabricated utilizing radio frequency sputter coating and photoresist lift-off techniques. Electrical characterizations are performed on two designs in order to investigate the feasibility of generating small amounts of power, utilizing any available waste heat as the energy source.

  1. Multiferroics: progress and prospects in thin films.

    PubMed

    Ramesh, R; Spaldin, Nicola A

    2007-01-01

    Multiferroic materials, which show simultaneous ferroelectric and magnetic ordering, exhibit unusual physical properties - and in turn promise new device applications - as a result of the coupling between their dual order parameters. We review recent progress in the growth, characterization and understanding of thin-film multiferroics. The availability of high-quality thin-film multiferroics makes it easier to tailor their properties through epitaxial strain, atomic-level engineering of chemistry and interfacial coupling, and is a prerequisite for their incorporation into practical devices. We discuss novel device paradigms based on magnetoelectric coupling, and outline the key scientific challenges in the field. PMID:17199122

  2. Sculptured-thin-film plasmonic-polaritonics

    E-print Network

    Lakhtakia, A; Motyka, M A

    2008-01-01

    The solution of a boundary--value problem formulated for the Kretschmann configuration shows that the phase speed of a surface--plasmon--polariton (SPP) wave guided by the planar interface of a sufficiently thin metal film and a sculptured thin film (STF) depends on the vapor incidence angle used while fabricating the STF by physical vapor deposition. Furthermore, it may be possible to engineer the phase speed by periodically varying the vapor incidence angle. The phase speed of the SPP wave can be set by selecting higher mean value and/or the modulation amplitude of the vapor incidence angle.

  3. A torque magnetometer for thin films applications

    NASA Astrophysics Data System (ADS)

    Rigue, J.; Chrischon, D.; de Andrade, A. M. H.; Carara, M.

    2012-04-01

    We describe the development of an automatic torque magnetometer based on a torsion pendulum. The instrument uses the capacitive arrange developed by Randall D. Peters, Rev. Sci. Instr. 60 (8), 2789 (1989), as sample's angular position sensor. The instrument performance is illustrated by measuring the in plane magnetic anisotropy of Co thin films and systems with exchange-bias. It possesses a sensitivity of 10?10 Nm and is capable to determine anisotropy constants in magnetic films as thin as 3 nm. The instrument design and the measurement procedures are presented.

  4. Crystal Structure and Orientation in Thin Films

    Microsoft Academic Search

    G. I. Finch; A. G. Quarrell

    1933-01-01

    IN crystal growth, the well-known phenomenon of pseudomorphism extends to all three dimensions. Recently we have found that thin films of aluminium on platinum, of zinc oxide on zinc and of magnesium oxide on magnesium possess abnormal crystal structures. For example, aluminium, normally of face-centred cubic structure (a = 4.05 A.), when deposited as a sufficiently thin layer on face-centred

  5. Superconducting thin films, composites and junctions

    NASA Astrophysics Data System (ADS)

    Geballe, T. H.

    1986-12-01

    Low energy ion beam cleaning of the substrates prior to deposition has been found to enhance the quality of ultrathin (less than 100A) refractory superconducting Niobium, Vanadium films. Nb film as thin as 7A has been grown from which it has been possible to fabricate good superconducting tunnel junctions. Both the native films and the tunnel junctions can be thermally recycled without any degradation. In-situ surface studies along with transmission electron microscopy (EM) suggest the removal of the carbon atoms from the surface of the substrate and possibly that increased chemical reactivity of the substrate atoms are the causes of the improvement. Electron microscopy (EM) results indicate that the Nb films grow perfectly lattice matched to the sapphire substrate when the substrate is ion-beam cleaned. This strained-layer epitaxy is observed up to 40A, the maximum thickness investigated through EM. Good-quality tunnel junctions have been fabricated on ultrathin films of Nb. Absolute specific-heat measurements have been made through the metal-insulator transition in thin film Molybdenum (X) Germanium (1-X) determining the thermodynamic electronic density of states. Nb/Tantalum multilayered films prepared by magnetron sputtering have been studied by critical field measurements. The effects of substrate orientation and deposition temperature on the properties of the films has been determined. Considerable progress has been made in the design and construction of the new advance electron beam deposition facility.

  6. Amorphous thin-film solar cells

    Microsoft Academic Search

    W. Krühler

    1991-01-01

    This report gives an overview of the present status of thin-film solar cells made from hydrogenated amorphous semiconductors (a-Si:H, a-Ge:H) together with new results emphasizing the physics of amorphous materials and devices. Preparation techniques, quality and performances of a-Si:H and a-Ge:H films as well as solar cells with pin structures are reviewed. Dark and light current-voltage I(V) characteristics and spectral

  7. Thin-Film Encapsulated RF MEMS Switches

    Microsoft Academic Search

    Kevin D. Leedy; Richard E. Strawser; Rebecca Cortez

    2007-01-01

    A wafer-level thin-film encapsulation process has been demonstrated to package radio-frequency (RF) microelectromechanical systems (MEMS) switches in this paper. Individual shunt capacitive switches were packaged in a ~1nL inorganic enclosure with process temperatures not exceeding 300 degC. A shell covering the switch consisted of 10 nm of sputtered alumina and 1.67 mum of sputtered silicon nitride dielectric film. The switch

  8. Superconducting thin films on potassium tantalate substrates

    DOEpatents

    Feenstra, Roeland (Oak Ridge, TN); Boatner, Lynn A. (Oak Ridge, TN)

    1992-01-01

    A superconductive system for the lossless transmission of electrical current comprising a thin film of superconducting material Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-x epitaxially deposited upon a KTaO.sub.3 substrate. The KTaO.sub.3 is an improved substrate over those of the prior art since the it exhibits small lattice constant mismatch and does not chemically react with the superconducting film.

  9. Annealed CVD molybdenum thin film surface

    DOEpatents

    Carver, Gary E. (Tucson, AZ); Seraphin, Bernhard O. (Tucson, AZ)

    1984-01-01

    Molybdenum thin films deposited by pyrolytic decomposition of Mo(CO).sub.6 attain, after anneal in a reducing atmosphere at temperatures greater than 700.degree. C., infrared reflectance values greater than reflectance of supersmooth bulk molybdenum. Black molybdenum films deposited under oxidizing conditions and annealed, when covered with an anti-reflecting coating, approach the ideal solar collector characteristic of visible light absorber and infrared energy reflector.

  10. Oxynitride Thin Film Barriers for PV Packaging

    Microsoft Academic Search

    S. H. Glick; J. A. delCueto; K. M. Terwilliger; G. J. Jorgensen; J. W. Pankow; B. M. Keyes; L. M. Gedvilas; F. J. Pern

    2005-01-01

    Dielectric thin-film barrier and adhesion-promoting layers consisting of silicon oxynitride materials (SiOxNy, with various stoichiometry) were investigated. For process development, films were applied to glass (TCO, conductive SnO2:F; or soda-lime), polymer (PET, polyethylene terephthalate), aluminized soda-lime glass, or PV cell (a-Si, CIGS) substrates. Design strategy employed de-minimus hazard criteria to facilitate industrial adoption and reduce implementation costs for PV manufacturers

  11. PZT thin films grown by laser ablation

    Microsoft Academic Search

    Tupac Garcia; E. de Posada; Ernesto Jimenez; F. Calderon; P. Bartolo-Perez; J. L. Pena

    1999-01-01

    PZT thin films were deposited by laser ablation at high vacuum and at room temperature. After that, some of the samples were annealed at air in the temperature range 450 degree(s)C - 550 degree(s)C. The samples were characterized by XPS and X-ray diffraction. A decrease in the oxygen composition of the as-deposited sample was observed. In the as-deposited film metallic

  12. Physical properties in thin films of iron oxides

    Microsoft Academic Search

    J. D. Uribe; J. Osorio; C. A. Barrero; D. Girataa; A. L. Morales; A. Hoffmann

    2008-01-01

    We have grown hematite (?-Fe2O3) thin films on stainless steel substrates and magnetite (Fe3O4) thin films on (001)-Si single crystal substrates by a RF magnetron sputtering process. ?-Fe2O3 thin films were grown in an Ar atmosphere at substrate temperatures around 400?C, and Fe3O4 thin films in an Ar\\/O2 reactive atmosphere at substrate temperatures around 500?C. Conversion electron Mössbauer (CEM) spectra

  13. Growth Induced Magnetic Anisotropy in Crystalline and Amorphous Thin Films

    SciTech Connect

    Hellman, Frances

    1998-10-03

    OAK B204 Growth Induced Magnetic Anisotropy in Crystalline and Amorphous Thin Films. The work in the past 6 months has involved three areas of magnetic thin films: (1) amorphous rare earth-transition metal alloys, (2) epitaxial Co-Pt and hTi-Pt alloy thin films, and (3) collaborative work on heat capacity measurements of magnetic thin films, including nanoparticles and CMR materials.

  14. Processing of thin SU-8 films

    NASA Astrophysics Data System (ADS)

    Keller, Stephan; Blagoi, Gabriela; Lillemose, Michael; Haefliger, Daniel; Boisen, Anja

    2008-12-01

    This paper summarizes the results of the process optimization for SU-8 films with thicknesses <=5 µm. The influence of soft-bake conditions, exposure dose and post-exposure-bake parameters on residual film stress, structural stability and lithographic resolution was investigated. Conventionally, the SU-8 is soft-baked after spin coating to remove the solvent. After the exposure, a post-exposure bake at a high temperature TPEB >= 90 °C is required to cross-link the resist. However, for thin SU-8 films this often results in cracking or delamination due to residual film stress. The approach of the process optimization is to keep a considerable amount of the solvent in the SU-8 before exposure to facilitate photo-acid diffusion and to increase the mobility of the monomers. The experiments demonstrate that a replacement of the soft-bake by a short solvent evaporation time at ambient temperature allows cross-linking of the thin SU-8 films even at a low TPEB = 50 °C. Fourier-transform infrared spectroscopy is used to confirm the increased cross-linking density. The low thermal stress due to the reduced TPEB and the improved structural stability result in crack-free structures and solve the issue of delamination. The knowledge of the influence of different processing parameters on the responses allows the design of optimized processes for thin SU-8 films depending on the specific application.

  15. Preface: Thin films of molecular organic materials

    NASA Astrophysics Data System (ADS)

    Fraxedas, J.

    2008-03-01

    This special issue is devoted to thin films of molecular organic materials and its aim is to assemble numerous different aspects of this topic in order to reach a wide scientific audience. Under the term 'thin films', structures with thicknesses spanning from one monolayer or less up to several micrometers are included. In order to narrow down this relaxed definition (how thin is thin?) I suggest joining the stream that makes a distinction according to the length scale involved, separating nanometer-thick films from micrometer-thick films. While the physical properties of micrometer-thick films tend to mimic those of bulk materials, in the low nanometer regime new structures (e.g., crystallographic and substrate-induced phases) and properties are found. However, one has to bear in mind that some properties of micrometer-thick films are really confined to the film/substrate interface (e.g. charge injection), and are thus of nanometer nature. Supported in this dimensionality framework, this issue covers the most ideal and model 0D case, a single molecule on a surface, through to the more application-oriented 3D case, placing special emphasis on the fascinating 2D domain that is monolayer assembly. Thus, many aspects will be reviewed, such as single molecules, self-organization, monolayer regime, chirality, growth, physical properties and applications. This issue has been intentionally restricted to small molecules, thus leaving out polymers and biomolecules, because for small molecules it is easier to establish structure--property relationships. Traditionally, the preparation of thin films of molecular organic materials has been considered as a secondary, lower-ranked part of the more general field of this class of materials. The coating of diverse surfaces such as silicon, inorganic and organic single crystals, chemically modified substrates, polymers, etc., with interesting molecules was driven by the potential applications of such molecular materials/substrate systems (also called heterostructures) based on the physical properties of the bulk materials, usually in the form of single crystals. However, in recent years the thin films community has been continually growing, helping the field to mature. In my opinion two main aspects have advanced the thin molecular films field. The first is the different applications with optical and electrical devices such as OFETs (organic field-effect transistors) and OLEDs (organic light emitting diodes), applications that could not have been achieved with single crystals because of limited size, difficult processability and mechanical fragility. The second is the involvement of the surface science community with their overwhelming arsenal of experimental techniques. From the synthesis point of view, the preparation of thin films is being regarded as a complementary synthesis route. The different externally accessible variables involved in the preparation process (temperature, pressure, molecular flux, distance, time, concentration, solvent, substrate, etc.), which define the so-called parameter hyperspace, can be so diverse when comparing competing synthesis routes (e.g. solution versus vapour growth) that we should not be surprised if different crystallographic phases with different morphologies are obtained, even if metastable. We should not forget here that the amazingly large number of available molecules is due to the longstanding and innovative work of synthesis chemists, a task that has not been sufficiently recognized (laymen in the domain of synthesis of organic molecules tend to believe that almost any molecule can be synthesized). In summary, one of the goals of this issue is to highlight the emerging importance of the field of thin molecular organic films by giving selected examples. It is clear that some important examples are missing, which are due in part to space limitation and to the understandable reluctance of highly-ranked specialists to contribute because of work overload. Among these not included but not forgotten subjects we can list films showing linear and non

  16. Phonon wave heat conduction in thin films and superlattices

    Microsoft Academic Search

    G. Chen

    1999-01-01

    Heat conduction in thin films and superlattices is important for many engineering applications such as thin-film based microelectronic, photonic, thermoelectric, and thermionic divides. Past modeling efforts on the thermal conductivity of thin films were based on solving the Boltzmann transport equation that treats phonons as particles. The effects of phonon interference and tunneling on the heat conduction and the thermal

  17. VACUUM PUMPING STUDY OF TITANIUM-ZIRCONIUM-VANADIUM THIN FILMS*

    E-print Network

    ERL 03-8 VACUUM PUMPING STUDY OF TITANIUM-ZIRCONIUM-VANADIUM THIN FILMS* Yulin Li# and Simon Ho performance of Titanium- Zirconium-Vanadium (TiZrV) NEG thin films was investigated to provide `engineering- Zirconium-Vanadium (TiZrV) NEG thin films, deposited on the interior of stainless steel (SST) pipes. The Ti

  18. Emerging Trends in Research on Sculptured Thin Films

    E-print Network

    Lakhtakia, Akhlesh

    Emerging Trends in Research on Sculptured Thin Films Akhlesh Lakhtakia Department of Engineering;INTRODUCTION #12;SPIE Press (2005) #12;Sculptured Thin Films Assemblies of Parallel Curved Nanowires/Submicronwires Controllable Nanowire Shape #12;#12;Sculptured Thin Films Assemblies of Parallel Curved Nanowires

  19. Apparatus for temperature programmed desorption studies of thin films

    Microsoft Academic Search

    Babu R. Chalamala; David Uebelhoer; Robert H. Reuss

    2000-01-01

    A versatile analytical system based on thermal desorption spectroscopy of thin films is presented. We have found the apparatus to be a useful tool for measuring the desorption characteristics of trapped gases in physical vapor deposited thin films and in determining the thermal stability of multi-component thin film compounds and multilayer structures. The system was also found to be a

  20. Growth induced magnetic anisotropy in crystalline and amorphous thin films

    SciTech Connect

    Hellman, F.

    1998-07-20

    The work in the past 6 months has involved three areas of magnetic thin films: (1) amorphous rare earth-transition metal alloys, (2) epitaxial Co-Pt and Ni-Pt alloy thin films, and (3) collaborative work on heat capacity measurements of magnetic thin films, including nanoparticles and CMR materials. A brief summary of work done in each area is given.

  1. Thin film semiconductor solar cell array and method of making

    Microsoft Academic Search

    C. R. Dickson; B. J. Johnson; D. B. Gerhardt

    1990-01-01

    This patent describes a multi-cell thin-film semiconductor device fabricated by a process. The process comprises: fabricating a plurality of spaced-apart front electrodes on a substrate; fabricating a thin film of semiconductor material on the front electrodes; fabricating a thin film of metal on the semiconductor film; scribing the metal film along a pattern of first lines with a laser operated

  2. Optimization of YBa sub 2 Cu sub 3 O sub 7 thin films for multilayers

    SciTech Connect

    Humphreys, R.G.; Chew, N.G.; Satchell, J.S.; Goodyear, S.W.; Edwards, J.A.; Blenkinsop, S.E. (Royal Signals and Radar Establishment, Malvern (United Kingdom))

    1991-03-01

    This paper studies the in situ growth of YBa{sub 2}Cu{sub 3}O{sub 7} thin films using e-beam coevaporation. The growth conditions for smooth YBa{sub 2}Cu{sub 3}O{sub 7} films with high T{sub c} and J{sub c} have been established. Superconductor-insulator and SIS structures have been grown using Y{sub 2}O{sub 3} as an epitaxial insulator, and preliminary vertical transport measurements in patterned structures are reported.

  3. Microstructural characterization in nanocrystalline ceramic thin films

    NASA Astrophysics Data System (ADS)

    Kim, Hakkwan

    The primary objective of this research is to investigate the effects of process variables on microstructure in several fluoride and oxide thin films prepared by vapor deposition, in order to predict the properties and behaviors of nanocrystalline thin film materials. There are three distinct stages of this research. The first stage focuses on measuring of the porosity in polycrystalline thin films of a variety of fluorides as a function of the substrate temperature during deposition, and discussing the mechanism by which the porosity varies as a function of the process variables. We have measured the porosity in thin films of lithium fluoride (LiF), magnesium fluoride (MgF2), barium fluoride (BaF 2) and calcium fluoride (CaF2) using an atomic force microscope (AFM) and a quartz crystal thickness monitor. The porosity is very sensitive to the substrate temperature and decreases as the substrate temperature increases. Consistent behavior is observed among all of the materials in this study. The second stage is to understand the film microstructure including grain growth and texture development, because these factors are known to influence the behavior and stability of polycrystalline thin films. This study focuses on grain growth and texture development in polycrystalline lithium fluoride thin films using dark field (DF) transmission electron microscopy (TEM). It is demonstrated that we can isolate the size distribution of <111> surface normal grains from the overall size distribution, based on simple and plausible assumptions about the texture. The {111} texture formation and surface morphology were also observed by x-ray diffraction (XRD) and AFM, respectively. The grain size distributions become clearly bimodal as the annealing time increases, and we deduce that the short-time size distributions are also a sum of two overlapping peaks. The smaller grain-size peak in the distribution corresponds to the {111}-oriented grains which do not grow significantly, while all other grains increase in size with annealing time. A novel feature of the LiF films is that the {111} texture component strengthens with annealing, despite the absence of growth for these grains, through the continued nucleation of new grains. The third stage focuses on the evaluation of triple junction energy in nanocrystalline ZrO2 thin films. Grain boundaries and triple junctions are important aspects of the microstructure of most crystalline materials, and it is necessary to understand them to be able to predict the behavior of bulk polycrystals and polycrystalline thin films. Triple junctions, where three grains or grain boundaries meet, become increasingly important in nanocrystalline materials where they occupy an increasing fraction of the total volume of the material. It would therefore be of great significance to know whether, and if so how triple junction energy varies. In this study we evaluate triple junction energies in nanocrystalline ZrO2 thin films using thickness mapping images produced by energy filtered transmission electron microscopy (EFTEM), which enable us to measure the surface topography associated with grain boundaries and triple junctions. In our films, the triple junction energy is deduced to be either zero (within the accuracy of the measurement) for most, but significantly positive for a few of the junctions.

  4. Residual stress measurement in YBCO thin films.

    SciTech Connect

    Cheon, J. H.; Singh, J. P.

    2002-05-13

    Residual stress in YBCO films on Ag and Hastelloy C substrates was determined by using 3-D optical interferometry and laser scanning to measure the change in curvature radius before and after film deposition. The residual stress was obtained by appropriate analysis of curvature measurements. Consistent with residual thermal stress calculations based on the thermal expansion coefficient mismatch between the substrates and YBCO film, the measured residual stress in the YBCO film on Hastelloy C substrate was tensile, while it was compressive on the Ag substrate. The stress values measured by the two techniques were generally in good agreement, suggesting that optical interferometry and laser scanning have promise for measuring residual stresses in thin films.

  5. Ferrite thin films for microwave applications

    SciTech Connect

    Zaquine, I.; Benazizi, H.; Mage, J.C.

    1988-11-15

    Production of ferrite thin films is the key to integration of microwave ferrite devices (circulators for phased array antennas, for instance). The interesting materials are the usual microwave ferrites: garnets, lithium ferrites, barium hexaferrites. The required thicknesses are a few tens of micrometers, and it will be important to achieve high deposition rates. Different substrates can be used: silicon and alumina both with and without metallization. The films were deposited by rf sputtering from a single target. The as-deposited films are amorphous and therefore require careful annealing in oxygen atmosphere. The sputtered films are a few micrometers thick on 4 in. substrates. The optimum annealing temperature was found by trying to obtain the highest possible magnetization for each ferrite. The precision on the value of magnetization is limited by the precision on the thickness of the film. We obtain magnetization values slightly lower than the target's. The ferromagnetic resonance linewidth was measured on toroids from 5 to 18 GHz.

  6. FMR in Multilayer Magnetic Thin Films

    Microsoft Academic Search

    Abdelhamid Layadi

    1989-01-01

    We have used Ferromagnetic Resonance (FMR) to investigate a variety of coupled magnetic thin films. Two types of phenomena have been studied: (1) the interaction between a ferromagnetic and an antiferromagnetic layer (known as interfacial exchange anisotropy), (2) the interaction between two ferromagnetic layers separated by a non-magnetic interlayer. In the first category we carried out experiments, with both 9

  7. Confinement effects on thin polymer films

    Microsoft Academic Search

    Karoly J. T. Dalnoki-Veress

    1998-01-01

    We present the results of four projects investigating the effects of confinement on polymeric systems. The first study dealt with polymer blends that are quenched using a spincoating technique rather than a temperature quench. The mass fraction of two blends was varied to determine the effect of the substrate-blend interface on the thin film phase separation morphology. Quantitative measurements of

  8. Plasmonics in Thin Film Solar Cells

    Microsoft Academic Search

    Stephan Fahr; Carsten Rockstuhl; Falk Lederer

    2009-01-01

    Thin film solar cells made of amorphous or microcrystalline silicon provide renewable energy at the benefits of low material consumption. As a drawback, these materials don't offer the high carrier mobilities of their crystalline counterpart. Due to low carrier mobilities, increased process times and material consumption, thick absorbing layers have to be avoided. For maintaining the absorption of the impinging

  9. Anelasticity in freestanding aluminum thin films

    Microsoft Academic Search

    Paul A. El-Deiry

    2005-01-01

    Anelastic deformation is present in all metals, but it is generally negligible in bulk form and at low homologous temperatures. In thin films, anelastic deformation contributes a great deal to the overall mechanical properties. Anelastic deformation is any portion of the total deformation of a body that occurs as a function of time when load is applied and which disappears

  10. Synthesis and characterization of multiferroic thin films

    Microsoft Academic Search

    Sung Hwan Lim

    2008-01-01

    Multiferroic materials and multiferroic materials systems which simultaneously exhibit ferroelectricity and magnetism have attracted great attention because of their exotic physical properties and their potential applications which utilize coupling of magnetism and ferroelectricity. The goal of this thesis was to study multiferroic materials systems in thin film and multilayer forms in order to explore the possibility of fabricating room temperature

  11. Multiferroics and magnetoelectrics: thin films and nanostructures

    Microsoft Academic Search

    L. W. Martin; S. P. Crane; Y.-H. Chu; M. B. Holcomb; M. Gajek; M. Huijben; C.-H. Yang; N. Balke; R. Ramesh

    2008-01-01

    Multiferroic materials, or materials that simultaneously possess two or more ferroic order parameters, have returned to the forefront of materials research. Driven by the desire to achieve new functionalities---such as electrical control of ferromagnetism at room temperature---researchers have undertaken a concerted effort to identify and understand the complexities of multiferroic materials. The ability to create high quality thin film multiferroics

  12. Thin-Film Solid Oxide Fuel Cells

    NASA Technical Reports Server (NTRS)

    Chen, Xin; Wu, Nai-Juan; Ignatiev, Alex

    2009-01-01

    The development of thin-film solid oxide fuel cells (TFSOFCs) and a method of fabricating them have progressed to the prototype stage. This can result in the reduction of mass, volume, and the cost of materials for a given power level.

  13. Semiconductor cooling by thin-film thermocouples

    NASA Technical Reports Server (NTRS)

    Tick, P. A.; Vilcans, J.

    1970-01-01

    Thin-film, metal alloy thermocouple junctions do not rectify, change circuit impedance only slightly, and require very little increase in space. Although they are less efficient cooling devices than semiconductor junctions, they may be applied to assist conventional cooling techniques for electronic devices.

  14. Analysis of hydrogen isotopes in thin films

    Microsoft Academic Search

    T. K. Mehrhoff; J. O. Humphries

    1976-01-01

    Mass spectrometer modifications made for high resolution analysis of hydrogen isotopes outgassed from occluder thin films are described. The electronic modifications made to the source, magnet power supply, and scanning circuits provided increased precision in the mass range 2 to 6. Routine analyses were made at a resolution of 1300 with a Faraday cup detector. Extensive modification of the inlet

  15. Thin film thermocouples for internal combustion engines

    Microsoft Academic Search

    Kenneth G. Kreider

    1986-01-01

    The feasibility of fabricating thin film thermocouples on internal combustion engine hardware was investigated. The goal was to find a procedure that would be useful for the measurement of the surface metal temperature of valves, valve seats, combustion chamber surfaces, cylinder walls, and piston heads during engine operation. The approach pursued was to coat the engine hardware material with an

  16. Surface, interface, and thin-film magnetism

    Microsoft Academic Search

    L. M. Falicov; Daniel T. Pierce; S. D. Bader; R. Gronsky; Kristl B. Hathaway; Herbert J. Hopster; David N. Lambeth; S. S. P. Parkin; Gary Prinz; Myron Salamon; Ivan K. Schuller; R. H. Victora

    1990-01-01

    A comprehensive review and state of the art in the field of surface, interface and thin-film magnetism is presented. New growth techniques which produce atomically engineered novel materials, special characterization techniques to measure magnetic properties of low-dimensional systems, and computational advances which allow large complex calculations have together stimulated the current activity in this field and open new opportunities for

  17. Flexoelectricity in barium strontium titanate thin film

    NASA Astrophysics Data System (ADS)

    Kwon, Seol Ryung; Huang, Wenbin; Shu, Longlong; Yuan, Fuh-Gwo; Maria, Jon-Paul; Jiang, Xiaoning

    2014-10-01

    Flexoelectricity, the linear coupling between the strain gradient and the induced electric polarization, has been intensively studied as an alternative to piezoelectricity. Especially, it is of interest to develop flexoelectric devices on micro/nano scales due to the inherent scaling effect of flexoelectric effect. Ba0.7Sr0.3TiO3 thin film with a thickness of 130 nm was fabricated on a silicon wafer using a RF magnetron sputtering process. The flexoelectric coefficients of the prepared thin films were determined experimentally. It was revealed that the thin films possessed a transverse flexoelectric coefficient of 24.5 ?C/m at Curie temperature (˜28 °C) and 17.44 ?C/m at 41 °C. The measured flexoelectric coefficients are comparable to that of bulk BST ceramics, which are reported to be 10-100 ?C/m. This result suggests that the flexoelectric thin film structures can be effectively used for micro/nano-sensing devices.

  18. Residual stresses in MEMS thin films

    Microsoft Academic Search

    Xin Zhang

    1998-01-01

    Residual stresses in thin films are always a major concern in micromachining technology. The present work studies (1) behavior of residual stresses; (2) measurements of residual stresses; and (3) control and\\/or elimination of residual stresses. In-situ observations of buckling evolution of a polysilicon microbearn during etch of its underneath sacrificial layer were carried out. As etching went on, the buckling

  19. Nucleate boiling in thin liquid films

    Microsoft Academic Search

    P. J. Marto; D. K. MacKenzie; A. D. Rivers

    1977-01-01

    Experimental results are presented for distilled water, ethyl alcohol and Freon-113 at atmospheric pressure with liquid levels ranging from pool depths of 25 mm down to thin films near 0.5 mm. Pool boiling data compare favorably with the Rohsenow correlation. Temperature measurements with thermocouples and liquid crystals show that liquid level has little effect on the heat transfer coefficient above

  20. Zinc Oxide Transparent Thin Films For Optoelectronics

    Microsoft Academic Search

    Karthik Sivaramakrishnan

    2010-01-01

    The object of this body of work is to study the properties and suitability of zinc oxide thin films with a view to engineering them for optoelectronics applications, making them a cheap and effective alternative to indium tin oxide (ITO), the most used transparent conducting oxides in the industry. Initially, a study was undertaken to examine the behavior of silver

  1. Aspects of passive magnetic levitation based on high-T(sub c) superconducting YBCO thin films

    NASA Technical Reports Server (NTRS)

    Schoenhuber, P.; Moon, F. C.

    1995-01-01

    Passive magnetic levitation systems reported in the past were mostly confined to bulk superconducting materials. Here we present fundamental studies on magnetic levitation employing cylindrical permanent magnets floating above high-T(sub c) superconducting YBCO thin films (thickness about 0.3 mu m). Experiments included free floating rotating magnets as well as well-established flexible beam methods. By means of the latter, we investigated levitation and drag force hysteresis as well as magnetic stiffness properties of the superconductor-magnet arrangement. In the case of vertical motion of the magnet, characteristic high symmetry of repulsive (approaching) and attractive (withdrawing) branches of the pronounced force-displacement hysteresis could be detected. Achievable force levels were low as expected but sufficient for levitation of permanent magnets. With regard to magnetic stiffness, thin films proved to show stiffness-force ratios about one order of magnitude higher than bulk materials. Phenomenological models support the measurements. Regarding the magnetic hysteresis of the superconductor, the Irie-Yamafuji model was used for solving the equation of force balance in cylindrical coordinates allowing for a macroscopic description of the superconductor magnetization. This procedure provided good agreement with experimental levitation force and stiffness data during vertical motion. For the case of (lateral) drag force basic qualitative characteristics could be recovered, too. It is shown that models, based on simple asymmetric magnetization of the superconductor, describe well asymptotic transition of drag forces after the change of the magnet motion direction. Virgin curves (starting from equilibrium, i.e. symmetric magnetization) are approximated by a linear approach already reported in literature only. This paper shows that basic properties of superconducting thin films allow for their application to magnetic levitation or - without need of levitation forces, e.g. microgravity - magnetic damping devices.

  2. Fracture of nanoporous thin-film glasses.

    PubMed

    Guyer, Eric P; Dauskardt, Reinhold H

    2004-01-01

    Fracture of nanoporous thin-film glasses is a significant challenge for the integration of these mechanically fragile materials in emerging microelectronic and biological technologies. In particular, the integration of these materials has been limited by accelerated cracking rates in moist environments leading to premature failure. Here, we demonstrate how cracking is affected by aqueous solution chemistry, and reveal anomalously high crack-growth rates in hydrogen peroxide solutions frequently encountered during device processing or when in use. Kinetic mechanisms involving the transport and steric hindrance of reactive hydrogen peroxide molecules at the crack tip are proposed. Thin-film design strategies that involve energy dissipation by local plasticity in thin ductile layers on increasing the resistance to cracking of nanoporous glass layers is demonstrated. Understanding how aqueous solutions influence cracking and associated device reliability is a fundamental challenge for these promising materials to be viable candidates for new technologies. PMID:14661017

  3. Thin film multiferroic nanocomposites by ion implantation.

    PubMed

    Algueró, Miguel; Ricote, Jesús; Torres, María; Amorín, Harvey; Alberca, Aurora; Iglesias-Freire, Oscar; Nemes, Norbert; Holgado, Susana; Cervera, Manuel; Piqueras, Juan; Asenjo, Agustina; García-Hernández, Mar

    2014-02-12

    Thin film multiferroic nanocomposites might enable a range of potentially disruptive integrated magnetoelectric devices for information storage, spintronics, microwave telecommunications, and magnetic sensing. With this aim, we have investigated ion implantation of magnetic species into ferroelectric single crystal targets as a radically novel approach to prepare film nanoparticulate magnetic-metal ferroelectric-oxide composites. These materials are an alternative to multiferroic oxide epitaxial columnar nanostructures that are under intensive research, but whose magnetoelectric response is far from expectations. Here, we unambiguously demonstrate the preparation of such a thin film multiferroic nanocomposite of Co and BaTiO3 by ion implantation of a high dose of the magnetic species, followed by rapid thermal processing under tailored conditions. Results thus constitute a proof of concept for the feasibility of obtaining the materials by this alternative approach. Ion implantation is a standard technique for the microelectronic industry in combination with well-established patterning procedures. PMID:24417708

  4. Quasi-monocrystalline silicon for thin-film devices

    Microsoft Academic Search

    T. J. Rinke; R. B. Bergmann; J. H. Werner

    1999-01-01

    .   Thermal crystallization of a double layer porous Si film creates a monocrystalline Si film with a thin separation layer between\\u000a the Si film and the reusable starting wafer. The process enables transfer of thin monocrystalline Si films to foreign substrates,\\u000a whereby devices may be formed before or after separation of the film. Sub-micrometer thick films are almost compact, while

  5. Thin film magnetic memory elements

    NASA Astrophysics Data System (ADS)

    Prinz, Gary Z.

    1989-06-01

    This invention is directed to a high density magnetic film memory storage device, and more particularly to such a memory storage device wherein the individual storage elements are patterned on a substrate using the intrinsic and structural anisotropies of the particular magnetic film, such that fringing fields about each storage element are eliminated. The first commercial random access nonvolatile magnetic memories were magnetic core systems in which circular magnetic ferrite cores were used as memory element, were arranged in large three-dimensional arrays, and were coupled to selected wire wraps for reading and writing.

  6. Structure of Nafion Thin Films on Gold

    NASA Astrophysics Data System (ADS)

    Weber, Adam; Kusoglu, Ahmet; Hexemer, Alexander

    2015-03-01

    Nafion is the prototypical ionomer in electrochemical energy devices due to its good ionic conductivity and permselectivity. In most devices, ionomers are in contact with precious metal catalysts. When confined to nanometer-thick ``thin'' films (10 to 100 nm), Nafion's morphology and associated transport properties deviate from the bulk. These changes are a function of the substrate and film thickness. In this talk, results from a systematic study of Nafion thin-film morphology on gold substrate using Grazing-incidence X-Ray Scattering (GISAXS) will be presented. GISAXS experiments carried out for a range of incident angles combined with the simulations of the electron density are used to demonstrate that the collected patterns are real and show an anisotropic long-range structural order that is strongest when the film thickness is around 50 nm and weakens for thicker and thinner films. Such ordering is not readily discernible on other substrates like carbon, nor with non-phase separated polymers like polystyrene. Results presented herein provide new insights into the key role of substrate/film interactions in inducing ordered structure in Nafion, which has implications for understanding ionomers interacting with various organic and inorganic materials in electrochemical devices. Supported by U. S. Department of Energy under Contract Number DE-AC02-05CH11231.

  7. Magnon dispersion in thin magnetic films

    NASA Astrophysics Data System (ADS)

    Balashov, T.; Buczek, P.; Sandratskii, L.; Ernst, A.; Wulfhekel, W.

    2014-10-01

    Although the dispersion of magnons has been measured in many bulk materials, few studies deal with the changes in the dispersion when the material is in the form of a thin film, a system that is of interest for applications. Here we review inelastic tunneling spectroscopy studies of magnon dispersion in Mn/Cu3Au(1?0?0) and present new studies on Co and Ni thin films on Cu(1?0?0). The dispersion in Mn and Co films closely follows the dispersion of bulk samples with negligible dependence on thickness. The lifetime of magnons depends slightly on film thickness, and decreases considerably as the magnon energy increases. In Ni/Cu(1?0?0) films the thickness dependence of dispersion is much more pronounced. The measurements indicate a considerable mode softening for thinner films. Magnon lifetimes decrease dramatically near the edge of the Brillouin zone due to a close proximity of the Stoner continuum. The experimental study is supported by first-principles calculations.

  8. Magnon dispersion in thin magnetic films.

    PubMed

    Balashov, T; Buczek, P; Sandratskii, L; Ernst, A; Wulfhekel, W

    2014-10-01

    Although the dispersion of magnons has been measured in many bulk materials, few studies deal with the changes in the dispersion when the material is in the form of a thin film, a system that is of interest for applications. Here we review inelastic tunneling spectroscopy studies of magnon dispersion in Mn/Cu3Au(1?0?0) and present new studies on Co and Ni thin films on Cu(1?0?0). The dispersion in Mn and Co films closely follows the dispersion of bulk samples with negligible dependence on thickness. The lifetime of magnons depends slightly on film thickness, and decreases considerably as the magnon energy increases. In Ni/Cu(1?0?0) films the thickness dependence of dispersion is much more pronounced. The measurements indicate a considerable mode softening for thinner films. Magnon lifetimes decrease dramatically near the edge of the Brillouin zone due to a close proximity of the Stoner continuum. The experimental study is supported by first-principles calculations. PMID:25212555

  9. Electrodeposition of CdTe thin films

    SciTech Connect

    Bhattachurya, R.N.; Rajeshwar, K.

    1984-09-01

    Cadmium telluride thin films were fabricated on Ti and Nesatron substrates by electrodeposition and characterized by x-ray diffraction, scanning electron microscopy, energy dispersive x-ray analyses (EDAX), optical transmission measurements, and photoelectrochemical (PEC) studies. The deposition-bath preparation procedure was slightly modified from the literature method to permit initial speciation of TeO/sub 2/ and thereby increase the loading level of Te in the film. New data are presented on the electrochemistry of the deposition process and on the cyclic voltammetric behavior of TeO/sub 2/ containing electrolytes in the pH range from about 0.7 to 11.0. The films after suitable annealing in an Ar atmosphere show x-ray diffraction behavior consistent with a hexagonal structure. Data from EDAX show that the Cd/Te ratio in the film is sensitive to the annealing process. Concomitantly, the conductivity also changes from p-type to n-type, as shown by PEC measurements on the films containing a protective ..cap alpha..-PbO/sub 2/ coating in contact with alkaline polysulfide electrolytes. Finally, some preliminary data are presented on PEC cells based on these CdTe thin films in a nonaqueous electrolyte system comprising the ferrocene/ferricenium ion redox couple.

  10. Thin film composite optical waveguides for sensor applications: a review.

    PubMed

    Yimit, Abliz; Rossberg, Axel G; Amemiya, Takashi; Itoh, Kiminori

    2005-03-15

    We review the design and fabrication of thin-film composite optical waveguides (OWG) with high refractive index for sensor applications. A highly sensitive optical sensor device has been developed on the basis of thin-film, composite OWG. The thin-film OWG was deposited onto the surface of a potassium-ion-exchanged (K(+)) glass OWG by sputtering or spin coating (5-9mm wide, and with tapers at both ends). By allowing an adiabatic transition of the guided light from the secondary OWG to the thin-film OWG, the electric field of the evanescent wave at the thin film was enhanced. The attenuation of the guided light in the thin film layer was small, and the guided light intensity changed sensitively with the refractive index of the cladding layer. Our experimental results demonstrate that thin-film, composite OWG gas sensors or immunosensors are much more sensitive than sensors based on other technologies. PMID:18969919

  11. Analytical characterization of thin carbon films.

    PubMed

    Ohr, R; Schug, C; Wahl, M; Wienss, A; Hilgers, H; Mahrholz, J; Willich, P; Jung, T

    2003-01-01

    CH(x) films on silicon substrates deposited by a Mesh Hollow Cathode Process (MHC) were analyzed by various techniques. The films were produced with varying deposition times, resulting in thicknesses ranging from ~2-20 nm. X-Ray Reflectivity (XRR) was used to determine the film thicknesses and the deposition rate. A good correlation of measured XRR thicknesses with SIMS sputter depths down to the film-substrate transition was found. An AFM-based nanoscratching technique was applied to test the wear resistance of the thin overcoats. The MHC films reveal slightly decreasing scratch resistance for reduced film thicknesses, which can be explained by a higher fraction of soft interface zones for thinner films. This is in accordance with Raman spectroscopic measurements in the visible spectral range which were carried out to examine the carbon bonding properties. Combined analysis of G peak position and D/G peak intensity ratio indicates a more graphitic structure for film thicknesses less than 10 nm. PMID:12520438

  12. A Multilayered Thin Film Insulator for Harsh Environments

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Fralick, Gustave C.; Blaha, Charles A.; Busfield, A. Rachel; Thomas, Valarie D.

    2002-01-01

    The status of work to develop a reliable high temperature dielectric thin film for use with thin film sensors is presented. The use of thin films to electrically insulate thin film sensors on engine components minimizes the intrusiveness of the sensor and allows a more accurate measurement of the environment. A variety of insulating films were investigated for preventing electrical shorting caused by insulator failure between the sensor and the component. By alternating layers of sputtered high temperature ceramics, a sequence of insulating layers was devised that prevents pinholes from forming completely through the insulator and maintains high electrical resistivity at high temperatures. The major technical challenge remaining is to optimize the fabrication of the insulator with respect to composition to achieve a reliable high temperature insulating film. Data from the testing of various potentially insulating thin film systems is presented and their application to thin film sensors is also discussed.

  13. Li ion backscattering study on high-Tc YBaCuO and GdBaCuO superconductor films

    NASA Astrophysics Data System (ADS)

    Wei-lin, Jiang; Zong-shuang, Zheng; Pei-ran, Zhu

    1993-01-01

    Rutherford backscattering (RBS) measurements of 4.2 MeV Li and 2.4 MeV He ions were done for YBaCuO and GdBaCuO high-Tc superconductor films deposited on MgO and SrTiO3 single crystalline substrates and for their bulk samples. Energy spectra of both ions were calculated using the RBS analysis program rewritten by the authors. Comparisons between these two non-destructive techniques showed some advantages in analyzing the layer thickness and composition ratios of those thin films by MeV Li ions backscattering. Estimated errors are within 7% for the measured elemental concentrations and 10% for the layer thickness in our experiments. A brief discussion is also made of the results.

  14. Ferroelectric Thin Films for Electronic Applications

    NASA Astrophysics Data System (ADS)

    Udayakumar, K. R.

    This study yokes together the feasibility of a family of PbO-based perovskite-structured ferroelectric thin films as functional elements in nonvolatile random access memories (NVRAMs), in high capacity dynamic RAMs, and in a new class of flexure wave piezoelectric ultrasonic micromotors. The dielectric and ferroelectric properties of lead zirconate titanate (PZT) thin films were dependent on thickness; at saturation, the films were characterized by a relative permittivity of 1300, remanent polarization of 36 muC/cm^2 and breakdown strength of over 1 MV/cm. The temperature dependence of permittivity revealed an anomalous behavior with the film annealing temperature. Based on the ferroelectric properties in the bulk, thin films in the lead zirconate -lead zinc niobate (PZ-PZN) solid solution system at 8-12% PZN, examined as alternate compositions for ferroelectric memories, feature switched charges of 4-14 mu C/cm^2, with coercive and saturation voltages less than the semiconductor operating voltage of 5 V. Rapid thermally annealed lead magnesium niobate titanate films were privy to weak signal dielectric permittivity of 2900, remanent polarization of 11 muC/cm^2, and a storage density of 210 fC/mum^2 at 5 V; the films merit consideration for potential applications in ultra large scale integrated circuits as also ferroelectric nonvolatile RAMs. The high breakdown strength and relative permittivity of the PZT films entail maximum stored energy density 10^3 times larger than a silicon electrostatic motor. The longitudinal piezoelectric strain coefficient d_{33 } was measured to be 220 pC/N at a dc bias of 75 kV/cm. The transverse piezoelectric strain coefficient d_{31} bore a nonlinear relationship with the electric field; at 200 kV/cm, d _{31} was -88 pC/N. The development of the piezoelectric ultrasonic micromotors from the PZT thin films, and the architecture of the stator structures are described. Nonoptimized prototype micromotors show rotational velocities of 100-300 rpm at drives of 3-5 V.

  15. Electronic processes in thin film PV materials

    NASA Astrophysics Data System (ADS)

    Taylor, P. C.; Gal, M.; Williams, G. A.; Ohlsen, W. D.

    1987-04-01

    One important class of materials for PV conversion of solar energy is the group of thin film amorphous semiconductors based on hydrogenated amorphous silicon (a-Si:H). Important alloys include a-Si(x)Ge(1-x):H and a-Si(x)C(1-x):H which are used to produce narrower gaps for tandem cells and lower band gaps for top-surface p-layers, respectively. Currently little is known concerning the defects and impurities which create enhanced densities of electronic states in the gap in these films. In addition, both the alloys and a-Si:H itself are currently plagued by electronically and optically induced mestabilities (Staebler-Wronski effect). The metastabilities adversely affect device performance and make projections of useful device lifetimes difficult. The roles of defects and impurities in this class of thin films are characterized. The quality of the interfaces and junctions which occur in PV devices are determined by employing surface-sensitive optical and resonant techniques. Another important objective is to understand the electronic metastabilites in the amorphous thin films.

  16. Optical properties of porous helical thin films.

    PubMed

    van Popta, Andy C; Sit, Jeremy C; Brett, Michael J

    2004-06-20

    Porous dielectric thin films, composed of isolated helical columns, are fabricated by the glancing angle deposition technique. The selective reflection of circularly polarized light and the optical rotation of linearly polarized light are investigated as a function of film material and helical morphology. The strongest chiral optical response is observed for titanium-dioxide films because of its large refractive index. Optical rotatory powers as high as 4.5 degrees are observed in 830-nm-thick helical films. By tailoring the pitch of the helical columns, the wavelength dependence of the circular reflection band is tuned to preferentially reflect red, green, or blue light, a promising quality for display applications. PMID:15218603

  17. O thin films prepared by electrodeposition

    NASA Astrophysics Data System (ADS)

    Jiang, Xishun; Zhang, Miao; Shi, Shiwei; He, Gang; Song, Xueping; Sun, Zhaoqi

    2014-05-01

    Cuprous oxide (Cu2O) thin films were prepared by using electrodeposition technique at different applied potentials (-0.1, -0.3, -0.5, -0.7, and -0.9 V) and were annealed in vacuum at a temperature of 100°C for 1 h. Microstructure and optical properties of these films have been investigated by X-ray diffractometer (XRD), field-emission scanning electron microscope (SEM), UV-visible (vis) spectrophotometer, and fluorescence spectrophotometer. The morphology of these films varies obviously at different applied potentials. Analyses from these characterizations have confirmed that these films are composed of regular, well-faceted, polyhedral crystallites. UV-vis absorption spectra measurements have shown apparent shift in optical band gap from 1.69 to 2.03 eV as the applied potential becomes more cathodic. The emission of FL spectra at 603 nm may be assigned as the near band-edge emission.

  18. Adhesion assessment of copper thin films

    SciTech Connect

    Kriese, M.D.; Gerberich, W.W. [Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemical Engineering; Moody, N.R. [Sandia National Labs., Livermore, CA (United States)

    1997-06-01

    Nano-indentation testing has been used to quantitatively assess the adhesion of thin copper films, sputtered to thicknesses of 150 nm to 1500 nm. Copper films of low residual stress were deposited via RF diode cathode sputtering onto SiO{sub 2}/Si substrates. Overlayers of DC magnetron sputtered tungsten, 850 nm thick with high residual stress, were additionally used to provide a driving force for delamination. All films tested exhibited buckle-driven delamination, from which the interfacial toughness was estimated to be 0.2 - 2 J/m{sup 2}, which is comparable to the thermodynamic work of adhesion. The use of an overlayer requires extensions of existing models, but otherwise does not change the interfacial adhesion, allowing measurements of films that would not otherwise delaminate.

  19. Microfabricated structures and devices featuring nanostructured titania thin films

    Microsoft Academic Search

    Adam J. Monkowski

    2007-01-01

    When titanium reacts with hydrogen peroxide at 80°C--100°C, a nanostructured titania (NST) thin film is formed on the titanium surface. This nanostructured film is particularly suited for integration with thin film and bulk microfabrication techniques. The ability to manufacture devices in a batch format is a principal advantage of microfabrication-based production. To reliably produce arrays of micro-patterned NST thin films

  20. Deposition and characterization of CuInS2 thin films deposited over copper thin films

    NASA Astrophysics Data System (ADS)

    Thomas, Titu; Kumar, K. Rajeev; Kartha, C. Sudha; Vijayakumar, K. P.

    2015-06-01

    Simple, cost effective and versatile spray pyrolysis method is effectively combined with vacuum evaporation for the deposition of CuIns2 thin films for photovoltaic applications. In the present study In2s3 was spray deposited over vacuum evaporated Cu thin films and Cu was allowed to diffuse in to the In2S3 layer to form CuInS2. To analyse the dependence of precursor volume on the formation of CuInS2 films structural, electrical and morphological analzes are carried out. Successful deposition of CuInS2thin films with good crystallinity and morphology with considerably low resistivity is reported in this paper.

  1. Borides in thin film technology

    SciTech Connect

    Mitterer, C. [Institut fuer Metallkunde und Werkstoffpruefung, Leoben (Austria)] [Institut fuer Metallkunde und Werkstoffpruefung, Leoben (Austria)

    1997-10-01

    The borides of transition and rare-earth metals are considered for application as wear- and corrosion-resistant, decorative or thermionic coatings. After a review of physical vapor deposition (PVD) techniques used for the deposition of these coatings, a survey of investigations to apply these coatings is given. As a result of the strong directionality of covalent boron-boron bonds, boride coatings show an increasing tendency to amorphous film growth with increasing B/Me atomic ratio and, for rare-earth hexaborides, with decreasing metallic radius of the rare-earth metal. Mechanical and optical properties are strongly influenced by the crystallographic structure of the boride phase. Because of their high hardness combined with good adhesion, crystalline films based on the diborides of transition metals seem to be promising candidates for wear resistant coatings on cutting tools. Alloying of these films with nitrogen by reactive PVD processes results in the formation of extremely fine-grained multiphase hard coatings with excellent tribological and corrosion behavior, thus offering new applications in the coating of engineering components. Because of their distinct colorations, some of the hexaborides of rare-earth elements may be used as decorative coatings on consumer products like wristwatch casings or eyeglass frames. Another promising field is the development of thermionic coatings based on rare-earth hexaborides, which may offer the possibility of the production of inexpensive and simple high emission filaments.

  2. Nanomechanics of thin films and surfaces

    NASA Astrophysics Data System (ADS)

    Jarausch, Konrad Frederick

    The nanoindentation and imaging capabilities of the interfacial force microscope (IFM) were used to explore how near surface and thin film mechanical properties correlate with microstructure and stress distributions (which are in turn determined by processing conditions). For single crystal Au samples, the critically resolved shear stress at yield was found to vary from 2 +/- 0.2 GPa for defect free regions, to 0.9 +/- 0.2 GPa in the presence of dislocations (intermediate values were recorded near grain boundaries and surface steps). The magnitude of the load-relaxation accompanying the onset of plasticity was found to scale with the strain energy stored in the material surrounding the contact immediately prior to yielding. Images and load-displacement curves demonstrate that yielding occurs in two stages: the first results in atomic scale permanent deformations while the second is characterized by large (greater than 10%) load relaxations and results in the pileup of material around the indenter. The images demonstrate that the onset of pileup is characterized by terraces raised in multiples of 0.25 nm above the initial surface and bounded by (111) planes. For 100 nm thick Au films, the measured elastic response was found to be reversibly dependent upon applied stress. Measurements of thin film elastic response appear to reflect a composite elasticity comprised of both bond and defect compliance. Measurements of the plastic deformation of individual grains in these films demonstrate that grain boundary sliding can accommodate plasticity at room temperature. Lower yield thresholds (2 GPa) were observed for intragranular deformation than for intergranular deformation (7 GPa). The application of tensile stress to the thin films was observed to favor grain boundary sliding. This work clearly demonstrates that once film thickness and deformation volumes shrink below 1 mum, a material's deposition and processing conditions (instead of the composition) become the principal determinate of the mechanical properties. These studies also highlight the utility of nanoindentation as a technique for measuring the mechanical properties on the nanometer scale.

  3. Thermal conductivities of thin, sputtered optical films

    SciTech Connect

    Henager, C.H. Jr.; Pawlewicz, W.T.

    1991-05-01

    The normal component of the thin film thermal conductivity has been measured for the first time for several advanced sputtered optical materials. Included are data for single layers of boron nitride (BN), aluminum nitride (AIN), silicon aluminum nitride (Si-Al-N), silicon aluminum oxynitride (Si-Al-O-N), silicon carbide (SiC), and for dielectric-enhanced metal reflectors of the form Al(SiO{sub 2}/Si{sub 3}N{sub 4}){sup n} and Al(Al{sub 2}O{sub 3}/AIN){sup n}. Sputtered films of more conventional materials like SiO{sub 2}, Al{sub 2}O{sub 3}, Ta{sub 2}O{sub 5}, Ti, and Si have also been measured. The data show that thin film thermal conductivities are typically 10 to 100 times lower than conductivities for the same materials in bulk form. Structural disorder in the amorphous or very fine-grained films appears to account for most of the conductivity difference. Conclusive evidence for a film/substrate interface contribution is presented.

  4. Electrohydrodynamic instabilities in thin liquid trilayer films

    DOE PAGESBeta

    Roberts, Scott A.; Kumar, Satish

    2010-09-12

    Experiments by Dickey et al. [Langmuir, 22, 4315 (2006)] and Leach et al. [Chaos, 15, 047506 (2005)] show that novel pillar shapes can be generated from electrohydrodynamic instabilities at the interfaces of thin polymer/polymer/air trilayer films. In this paper, we use linear stability analysis to investigate the effect of free charge and ac electric fields on the stability of trilayer systems. Our work is also motivated by our recent theoretical study [J. Fluid Mech., 631, 255 (2009)] which demonstrates how ac electric fields can be used to increase control over the pillar formation process in thin liquid bilayer films. Formore »perfect dielectric films, the effect of an AC electric field can be understood by considering an equivalent DC field. Leaky dielectric films yield pillar configurations that are drastically different from perfect dielectric films, and AC fields can be used to control the location of free charge within the trilayer system. This can alter the pillar instability modes and generate smaller diameter pillars when conductivities are mismatched. The results presented here may be of interest for the creation of complex topographical patterns on polymer coatings and in microelectronics.« less

  5. Modeling the superconductor-based magnetic traps for ultra-cold atoms

    E-print Network

    Prigozhin, Leonid

    Modeling the superconductor-based magnetic traps for ultra-cold atoms Leonid Prigozhin1, Vladimir characterizing the superconductor. Unlike the previous formulations of thin film magnetization problems written and coherence times of a magnetic trap is a high priority goal in the atom chip design. Superconductor nano

  6. Electrohydrodynamic instability of thin conductive liquid films

    NASA Astrophysics Data System (ADS)

    Wu, Xiang-Fa; Dzenis, Yuris A.

    2005-08-01

    This paper considers the effect of surface charges on the surface instability of thin conductive liquid films. A characteristic relation is obtained for determining the wave number of the fastest growing mode as a function of surface tension, dispersive van der Waals force and electrostatic tractions exerted by the film surface charges. Two natural length scales of the microsystem are further introduced to account for the coupling effects on the dewetting pattern development. The present results can be used for controlled surface pattern modulation in a spinodal-dewetting scenario via amplification of surface waves of selected modes.

  7. Nitrogen doped zinc oxide thin film

    SciTech Connect

    Li, Sonny X.

    2003-12-15

    To summarize, polycrystalline ZnO thin films were grown by reactive sputtering. Nitrogen was introduced into the films by reactive sputtering in an NO{sub 2} plasma or by N{sup +} implantation. All ZnO films grown show n-type conductivity. In unintentionally doped ZnO films, the n-type conductivities are attributed to Zn{sub i}, a native shallow donor. In NO{sub 2}-grown ZnO films, the n-type conductivity is attributed to (N{sub 2}){sub O}, a shallow double donor. In NO{sub 2}-grown ZnO films, 0.3 atomic % nitrogen was found to exist in the form of N{sub 2}O and N{sub 2}. Upon annealing, N{sub 2}O decomposes into N{sub 2} and O{sub 2}. In furnace-annealed samples N{sub 2} redistributes diffusively and forms gaseous N{sub 2} bubbles in the films. Unintentionally doped ZnO films were grown at different oxygen partial pressures. Zni was found to form even at oxygen-rich condition and led to n-type conductivity. N{sup +} implantation into unintentionally doped ZnO film deteriorates the crystallinity and optical properties and leads to higher electron concentration. The free electrons in the implanted films are attributed to the defects introduced by implantation and formation of (N{sub 2}){sub O} and Zni. Although today there is still no reliable means to produce good quality, stable p-type ZnO material, ZnO remains an attractive material with potential for high performance short wavelength optoelectronic devices. One may argue that gallium nitride was in a similar situation a decade ago. Although we did not obtain any p-type conductivity, we hope our research will provide a valuable reference to the literature.

  8. Inductance measurements in ? thin films

    NASA Astrophysics Data System (ADS)

    Cho, Shinho

    1997-08-01

    We present a new inductance measurement technique using a multi-frequency LCR meter. The inductance of superconducting 0953-2048/10/8/012/img2 (YBCO) delay lines was measured both as a function of temperature and bias current. The measured temperature dependence of the change in inductance for both meander and straight lines shows a square dependence on temperature, in good agreement with an unconventional pairing state. The effective magnetic penetration depth can be determined from the theoretical expression of the inductance for the case of a microstrip configuration with two identical superconducting films. The current-controlled inductance is well described by a modified Ginzburg - Landau equation.

  9. Polycrystalline thin films FY 1992 project report

    SciTech Connect

    Zweibel, K. (ed.)

    1993-01-01

    This report summarizes the activities and results of the Polycrystalline Thin Film Project during FY 1992. The purpose of the DOE/NREL PV (photovoltaic) Program is to facilitate the development of PV that can be used on a large enough scale to produce a significant amount of energy in the US and worldwide. The PV technologies under the Polycrystalline Thin Film project are among the most exciting next-generation'' options for achieving this goal. Over the last 15 years, cell-level progress has been steady, with laboratory cell efficiencies reaching levels of 15 to 16%. This progress, combined with potentially inexpensive manufacturing methods, has attracted significant commercial interest from US and international companies. The NREL/DOE program is designed to support the efforts of US companies through cost-shared subcontracts (called government/industry partnerships'') that we manage and fund and through collaborative technology development work among industry, universities, and our laboratory.

  10. Polycrystalline thin films FY 1992 project report

    SciTech Connect

    Zweibel, K. [ed.

    1993-01-01

    This report summarizes the activities and results of the Polycrystalline Thin Film Project during FY 1992. The purpose of the DOE/NREL PV (photovoltaic) Program is to facilitate the development of PV that can be used on a large enough scale to produce a significant amount of energy in the US and worldwide. The PV technologies under the Polycrystalline Thin Film project are among the most exciting ``next-generation`` options for achieving this goal. Over the last 15 years, cell-level progress has been steady, with laboratory cell efficiencies reaching levels of 15 to 16%. This progress, combined with potentially inexpensive manufacturing methods, has attracted significant commercial interest from US and international companies. The NREL/DOE program is designed to support the efforts of US companies through cost-shared subcontracts (called ``government/industry partnerships``) that we manage and fund and through collaborative technology development work among industry, universities, and our laboratory.

  11. Domain switching of fatigued ferroelectric thin films

    SciTech Connect

    Tak Lim, Yun [Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of); Yeog Son, Jong, E-mail: jyson@khu.ac.kr, E-mail: hoponpop@ulsan.ac.kr [Department of Applied Physics, College of Applied Science, Kyung Hee University, Suwon 446-701 (Korea, Republic of); Shin, Young-Han, E-mail: jyson@khu.ac.kr, E-mail: hoponpop@ulsan.ac.kr [Department of Physics and EHSRC, University of Ulsan, Ulsan 680-749 (Korea, Republic of)

    2014-05-12

    We investigate the domain wall speed of a ferroelectric PbZr{sub 0.48}Ti{sub 0.52}O{sub 3} (PZT) thin film using an atomic force microscope incorporated with a mercury-probe system to control the degree of electrical fatigue. The depolarization field in the PZT thin film decreases with increasing the degree of electrical fatigue. We find that the wide-range activation field previously reported in ferroelectric domains result from the change of the depolarization field caused by the electrical fatigue. Domain wall speed exhibits universal behavior to the effective electric field (defined by an applied electric field minus the depolarization field), regardless of the degree of the electrical fatigue.

  12. Multiferroic oxide thin films and heterostructures

    NASA Astrophysics Data System (ADS)

    Lu, Chengliang; Hu, Weijin; Tian, Yufeng; Wu, Tom

    2015-06-01

    Multiferroic materials promise a tantalizing perspective of novel applications in next-generation electronic, memory, and energy harvesting technologies, and at the same time they also represent a grand scientific challenge on understanding complex solid state systems with strong correlations between multiple degrees of freedom. In this review, we highlight the opportunities and obstacles in growing multiferroic thin films with chemical and structural integrity and integrating them in functional devices. Besides the magnetoelectric effect, multiferroics exhibit excellent resistant switching and photovoltaic properties, and there are plenty opportunities for them to integrate with other ferromagnetic and superconducting materials. The challenges include, but not limited, defect-related leakage in thin films, weak magnetism, and poor control on interface coupling. Although our focuses are Bi-based perovskites and rare earth manganites, the insights are also applicable to other multiferroic materials. We will also review some examples of multiferroic applications in spintronics, memory, and photovoltaic devices.

  13. Electrostatic Discharge Effects on Thin Film Resistors

    NASA Technical Reports Server (NTRS)

    Sampson, Michael J.; Hull, Scott M.

    1999-01-01

    Recently, open circuit failures of individual elements in thin film resistor networks have been attributed to electrostatic discharge (ESD) effects. This paper will discuss the investigation that came to this conclusion and subsequent experimentation intended to characterize design factors that affect the sensitivity of resistor elements to ESD. The ESD testing was performed using the standard human body model simulation. Some of the design elements to be evaluated were: trace width, trace length (and thus width to length ratio), specific resistivity of the trace (ohms per square) and resistance value. However, once the experiments were in progress, it was realized that the ESD sensitivity of most of the complex patterns under evaluation was determined by other design and process factors such as trace shape and termination pad spacing. This paper includes pictorial examples of representative ESD failure sites, and provides some options for designing thin film resistors that are ESD resistant. The risks of ESD damage are assessed and handling precautions suggested.

  14. Experimental Mechanics of MEMS and Thin Films

    Microsoft Academic Search

    Ioannis Chasiotis

    \\u000a The novel thin film materials manufactured for MEMS sensors, actuators, and multifunctional coatings demand the development\\u000a of novel methodologies for the characterization of their anisotropic mechanical properties, which dominate as submicron sized\\u000a devices become technologically feasible. While the limitations of continuum mechanics are experimentally still unexplored,\\u000a material anisotropy and scale-dependence of deformations require a combined experimental, analytical, and numerical approach

  15. Thin film transistor-addressed display device

    Microsoft Academic Search

    T. P. Brody; F. C. Luo; D. H. Davies

    1977-01-01

    This is the final report on Contract DAAB07-72-C-0061; the objective of which was an examination of the feasibility of fabricating a multielement dot-matrix display using electroluminescent output and an integrated thin film transistor addressing array. The concepts have been validated, good quality functional displays were made and delivered to the US Army. Three formats were examined: 6 in. x 6

  16. Modeling of polycrystalline thin film solar cells

    Microsoft Academic Search

    Alan L. Fahrenbruch

    1999-01-01

    This paper describes modeling polycrystalline thin-film solar cells using the program AMPS-1D1 to visualize the relationships between the many variables involved. These simulations are steps toward two dimensional modeling the effects of grain boundaries in polycrystalline cells. Although this paper describes results for the CdS\\/CdTe cell, the ideas presented here are applicable to copper-indium-gallium selenide (CIGS) cells as well as

  17. Degradation analysis of thin film photovoltaic modules

    Microsoft Academic Search

    C. Radue; E. E. van Dyk

    2009-01-01

    Five thin film photovoltaic modules were deployed outdoors under open circuit conditions after a thorough indoor evaluation. Two technology types were investigated: amorphous silicon (a-Si:H) and copper indium gallium diselenide (CIGS). Two 14W a-Si:H modules, labelled Si-1 and Si-2, were investigated. Both exhibited degradation, initially due to the well-known light-induced degradation described by Staebler and Wronski [Applied Physics Letters 31

  18. Thin Film Sensors for Surface Measurements

    NASA Technical Reports Server (NTRS)

    Martin, Lisa C.; Wrbanek, John D.; Fralick, Gustave C.

    2001-01-01

    Advanced thin film sensors that can provide accurate surface temperature, strain, and heat flux measurements have been developed at NASA Glenn Research Center. These sensors provide minimally intrusive characterization of advanced propulsion materials and components in hostile, high-temperature environments as well as validation of propulsion system design codes. The sensors are designed for applications on different material systems and engine components for testing in engine simulation facilities. Thin film thermocouples and strain gauges for the measurement of surface temperature and strain have been demonstrated on metals, ceramics and advanced ceramic-based composites of various component configurations. Test environments have included both air-breathing and space propulsion-based engine and burner rig environments at surface temperatures up to 1100 C and under high gas flow and pressure conditions. The technologies developed for these sensors as well as for a thin film heat flux gauge have been integrated into a single multifunctional gauge for the simultaneous real-time measurement of surface temperature, strain, and heat flux. This is the first step toward the development of smart sensors with integrated signal conditioning and high temperature electronics that would have the capability to provide feedback to the operating system in real-time. A description of the fabrication process for the thin film sensors and multifunctional gauge will be provided. In addition, the material systems on which the sensors have been demonstrated, the test facilities and the results of the tests to-date will be described. Finally, the results will be provided of the current effort to demonstrate the capabilities of the multifunctional gauge.

  19. Thin-film optical shutter. Final report

    SciTech Connect

    Matlow, S.L.

    1981-02-01

    A specific embodiment of macroconjugated macromolecules, the poly (p-phenylene)'s, has been chosen as the one most likely to meet all of the requirements of the Thin Film Optical Shutter project (TFOS). The reason for this choice is included. In order to be able to make meaningful calculations of the thermodynamic and optical properties of the poly (p-phenylene)'s a new quantum mechanical method was developed - Equilibrium Bond Length (EBL) Theory. Some results of EBL Theory are included.

  20. Lasing in liquid crystal thin films

    Microsoft Academic Search

    S. P. Palto

    2006-01-01

    A lasing condition is formulated in matrix form for optically anisotropic thin films. Lasing behavior of liquid-crystal slabs\\u000a is analyzed. In particular, it is shown that if the spatial extent of a liquid crystal slab is much larger than its thickness,\\u000a then laser emission is feasible not only along the normal to the slab, but also in the entire angular

  1. Thin-film organic polymer phototransistors

    Microsoft Academic Search

    Michael C. Hamilton; Sandrine Martin; Jerzy Kanicki

    2004-01-01

    We have studied the electrical performance of organic polymer thin-film transistors (OP-TFTs) under steady-state white-light illumination, as well as the performance of these devices as photodetectors. The off-state drain current of the OP-TFT is significantly increased due to the illumination, while a smaller relative effect is observed on the drain current in the strong-accumulation regime. The illumination effectively decreases the

  2. Structures for dense, crack free thin films

    DOEpatents

    Jacobson, Craig P. (Lafayette, CA); Visco, Steven J. (Berkeley, CA); De Jonghe, Lutgard C. (Lafayette, CA)

    2011-03-08

    The process described herein provides a simple and cost effective method for making crack free, high density thin ceramic film. The steps involve depositing a layer of a ceramic material on a porous or dense substrate. The deposited layer is compacted and then the resultant laminate is sintered to achieve a higher density than would have been possible without the pre-firing compaction step.

  3. Deposition of Thin Films by Sputtering

    Microsoft Academic Search

    W. Gulbi?ski

    \\u000a Thin films deposition techniques are generally classified in two main groups: Chemical Vapour Deposition (CVD) and Physical\\u000a Vapour Deposition (PVD). The last one encompasses sputtering and evaporation. They are applied, dependent on particular requirements\\u000a of the production technology. Obviously, they have their specific advantages and simultaneously introduce given limitations.\\u000a Below, selected PVD techniques will be classified and described in details.

  4. Fast organic thin-film transistor circuits

    Microsoft Academic Search

    Hagen Klauk; David J. Gundlach; Thomas N. Jackson

    1999-01-01

    We have fabricated organic thin-film transistors and integrated circuits using pentacene as the active material. Devices were fabricated on glass substrates using low-temperature ion-beam sputtered silicon dioxide as the gate dielectric and a double-layer photoresist process to isolate devices. These transistors have carrier mobility near 0.5 cm2\\/V-s and on\\/off current ratio larger than 107. Using a level-shifting design that allows

  5. Integrated radioactive thin films for sensing systems

    Microsoft Academic Search

    Amit Lal; Hui Li; Hang Guo

    2004-01-01

    Hybrid electromechanical systems with integrated power supplies are made possible with radioisotope thin films. A self-powered pressure transducer with pulsed radiofrequency (RF) output and a nanopower betavoltaic microbattery suitable for low-power CMOS are demonstrated in this paper. The pressure transducer collects charges emitted from the radioisotope with a dielectric cantilever to realize a self-reciprocating process, whose period is modulated by

  6. Thin film solar cells for terrestrial applications

    Microsoft Academic Search

    F. A. Shirland; W. J. Biter; E. W. Greeneich; T. P. Brody

    1975-01-01

    The goals of the project are to develop a terrestrial version of the CdS thin film solar cell that is demonstrably amenable to low cost mass production, and to establish data on the lifetime of such cells under the expected conditions of terrestrial use. There were six major tasks for the first year's work. These were: Re-establish the state-of-the-art of

  7. Deformation of spherulitic polyethylene thin films

    Microsoft Academic Search

    M. F. BUTLER; A. M. DONALD

    1997-01-01

    Thin spherulitic films of polyethylene (PE), made by casting from xylene solution, were deformed on copper grids and their\\u000a deformation microstructure studied using optical and transmission electron microscopy. A range of molecular weights, branch\\u000a amounts and types, and thermal histories was used to study the influence of sample microstructure on the deformation behaviour.\\u000a The spherulite boundaries were the weakest regions

  8. Interfaces in thin film solar cells

    Microsoft Academic Search

    A. Klein; W. Jaegermann; R. Hunger; D. Kraft; F. Sauberlich; T. Schulmeyer; B. Spath

    2005-01-01

    Interfaces are important for the efficiencies of thin film solar cells. In particular, for polycrystalline chalcogenide semiconductors as CdTe and Cu(In,Ga)(S,Se)2 (CIGS) the existing physical concepts, which describe the electronic properties of elemental or III-V compound semiconductor interfaces quite well, are not sufficient. The increased complexity is mostly due to the non-abruptness of the interfaces and the strong tendency for

  9. Magnetoelectric properties of magnetite thin films

    Microsoft Academic Search

    J S-Y Feng; R D Pashley; M-A Nicolet

    1975-01-01

    Resistivity, DC Hall effect and transverse magnetoresistance measurements were made on polycrystalline thin films of magnetite (Fe3O4) from 104K to room temperature. The Verwey transition is observed at TV=123K, about 4K higher than reported for bulk magnetite. The ordinary and extraordinary Hall coefficients are negative over the entire temperature range, consistent with negatively charged carriers. The extraordinary Hall coefficient exhibits

  10. Thin film dynamics of viscoelastic fluids

    NASA Astrophysics Data System (ADS)

    Lebon, Luc; Limat, Laurent

    2012-11-01

    We present here viscoelastic fluids in thin film flows, such as liquid bells or liquid curtains. The viscoelastic property of the liquids exhibits specific dynamics in such flows. In the case of bells, the elastic strength tends to extend the bell size for example. In the case of curtain flows, original behaviour of holes are observed with specific growth mechanism for bubbles trapped in the flow.

  11. Growth of epitaxial thin films by pulsed laser ablation

    SciTech Connect

    Lowndes, D.H.

    1992-10-01

    High-quality, high-temperature superconductor (HTSc) films can be grown by the pulsed laser ablation (PLA) process. This article provides a detailed introduction to the advantages and curent limitations of PLA for epitaxial film growth. Emphasis is placed on experimental methods and on exploitation of PLA to control epitaxial growth at either the unit cell or the atomic-layer level. Examples are taken from recent HTSc film growth. 33 figs, 127 refs. (DLC)

  12. Growth of epitaxial thin films by pulsed laser ablation

    SciTech Connect

    Lowndes, D.H.

    1992-01-01

    High-quality, high-temperature superconductor (HTSc) films can be grown by the pulsed laser ablation (PLA) process. This article provides a detailed introduction to the advantages and curent limitations of PLA for epitaxial film growth. Emphasis is placed on experimental methods and on exploitation of PLA to control epitaxial growth at either the unit cell or the atomic-layer level. Examples are taken from recent HTSc film growth. 33 figs, 127 refs. (DLC)

  13. Deposition of polycrystalline thin films with controlled grain size

    Microsoft Academic Search

    M. Vopsaroiu; G. Vallejo Fernandez; M. J. Thwaites; J. Anguita; P. J. Grundy; K. O'Grady

    2005-01-01

    Difficulties in controlling the grain size and size distribution in polycrystalline thin films are a major obstacle in achieving efficient performance of thin film devices. In this paper we describe a sputtering technology that allows the control of the grain size and size distribution in sputtered films without the use of seed layers, substrate heating or additives. This is demonstrated

  14. Black Silicon Enhanced Thin Film Silicon Photovoltaic Devices

    Microsoft Academic Search

    Martin U. Pralle; James E. Carey

    2010-01-01

    SiOnyx has developed an enhanced thin film silicon photovoltaic device with improved efficiency. Thin film silicon solar cells suffer from low material absorption characteristics resulting in poor cell efficiencies. SiOnyxs approach leverages Black Silicon, an advanced material fabricated using ultrafast lasers. The laser treated films show dramatic enhancement in optical absorption with measured values in excess of 90% in the

  15. Study on infrared optical switching of vanadium dioxide thin film

    Microsoft Academic Search

    Haifang Wang; Yi Li; Xiaojing Yu; Huiqun Zhu; Yize Huang; Hu Zhang; Wei Zhang

    2009-01-01

    Dispersion theory for refractive index and extinction coefficient of vanadium dioxide thin film is studied, and its temperature-dependence dispersion formula of optical constants is presented by numerical fitting with Sellmeier dispersion model. The optical transmittance and reflectance at different temperature and wavelength is calculated using film matrix theory. Vanadium dioxide thin films with different thickness are deposited by magnetron sputtering

  16. Chemical bath method for ZnS thin films preparation

    Microsoft Academic Search

    Andrés Iván Oliva; I. Gonza?lez-Chan; V. Rejo?n; J. Rojas; R. Patiño; D. Aguilar

    2010-01-01

    We report a chemical bath method to prepare ZnS thin films on glass substrates for solar applications. The proposed method is based on the experience to deposit CdS thin films by chemical bath but replacing some chemical reagents. The bath is composed of zinc chloride, potassium hydroxide, ammonium nitrate, and thiourea. During films deposition, the chemical bath is agitated with

  17. Ion irradiation of preceramic polymer thin films

    SciTech Connect

    Pivin, J.C. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, Orsay (France); Colombo, P.; Tonidandel, M. [Univ. di Padova (Italy)

    1996-07-01

    Thin films of two preceramic polymers, namely polycarbosilane (PCS) and a silicone resin (SR350), were deposited on Si substrates. Instead of employing conventional annealing at high temperatures in an inert atmosphere, ion irradiation was used to achieve the polymer-to-ceramic conversion. A detailed investigation of the changes in the composition, chemical structure, and hardness was performed by means of ion bean analysis (Rutherford backscattering spectrometry, nuclear reaction analysis, and elastic recoil detection analysis), FTIR, Raman and nanoindentation, respectively. This processing method yielded amorphous Si-C and Si-O-C coatings possessing high hardness and density. Compared to films heat-treated under vacuum at 1,000 C, ion-irradiated ones exhibited a similar hydrogen content, a lower oxygen contamination, and a higher carbon content. Annealing at 1,000 C of previously irradiated films resulted in coatings still possessing a high carbon content and a high hardness.

  18. Metal-doped magnetite thin films.

    PubMed

    Abe, Seishi; Ping, De Hai; Nakamura, Shintaro; Ohnuma, Masato; Ohnuma, Shigehiro

    2012-06-01

    This paper investigates magnetite (Fe3O4) thin film containing a small amount of a metal element. The films are prepared by rf sputtering with a composite target of ceramic iron oxide with metal chips. Low-temperature magnetization of magnetite containing 5.3%Ge reveals that the film contains some magnetically weak coupling grains. The metal element Mg reduces both hematite (alpha-Fe2O3) and magnetite, resulting in single-phase wüstite (Fe1-xO). In contrast, adding Ge selectively reduces hematite, while magnetite remains unreactive. According to the free energy of reaction, the element Ge is able to reduce hematite only, whereas the element Mg is capable of reducing both hematite and magnetite. This property is in good agreement with the experiment results. PMID:22905582

  19. Negative differential conductivity in thin ferroelectric films

    NASA Astrophysics Data System (ADS)

    Podgorny, Yury; Vorotilov, Konstantin; Sigov, Alexander

    2014-11-01

    A phenomenon of negative differential conductivity in ferroelectric thin films is discussed. We proposed that the reason is polarization recovery current arising at current-voltage I(V) measurements as a result of polarization relaxation after pre-polarization of ferroelectric film. Simulation of this current by Weibull distribution provides a good correlation with the experimental data. The obtained values of the recovered polarization Prec and the field strength Erec at which the recovery polarization current reaches maximum do not depend on the voltage sweep rate and are well correlated with the values of polarization relaxation Prel and coercive field strength Ec obtained from dielectric hysteresis loop. It is shown that the current density due to polarization recovery Jrec may exceed by about an order the ohmic current density J? in ferroelectric film at Ec.

  20. Ferroelectric Thin Films: Deposition, Advanced Film Characterization and Novel Device Concepts

    Microsoft Academic Search

    G. Suchaneck; G. Gerlach

    2006-01-01

    In this work, current problems of ferroelectric thin film deposition are reviewed: Film stoichiometry, mechanical film stress, and self-polarization. Advanced film characterization includes the profiling of film properties over film thickness: the refractive index by Multi Angle Spectroscopic Ellipsometry, the pyroelectric coefficient profile by Laser Intensity Modulation Method, and polarization and space charge profiling by Atomic Force Microscopy. Novel device

  1. Low-Cost Detection of Thin Film Stress during Fabrication

    NASA Technical Reports Server (NTRS)

    Nabors, Sammy A.

    2015-01-01

    NASA's Marshall Space Flight Center has developed a simple, cost-effective optical method for thin film stress measurements during growth and/or subsequent annealing processes. Stress arising in thin film fabrication presents production challenges for electronic devices, sensors, and optical coatings; it can lead to substrate distortion and deformation, impacting the performance of thin film products. NASA's technique measures in-situ stress using a simple, noncontact fiber optic probe in the thin film vacuum deposition chamber. This enables real-time monitoring of stress during the fabrication process and allows for efficient control of deposition process parameters. By modifying process parameters in real time during fabrication, thin film stress can be optimized or controlled, improving thin film product performance.

  2. Epitaxial thin films of the superconducting spinel oxide LiTi2O4

    NASA Astrophysics Data System (ADS)

    Chopdekar, Rajesh; Suzuki, Yuri

    2006-03-01

    Lithium titanate is the only superconducting spinel oxide documented in literature. Related oxide spinels[1] such as the heavy fermion system LiV2O4 and charge-ordered LiMn2O4 indicate that electron correlations are strong in these systems. We have fabricated epitaxial films of LiTi2O4 on MgAl2O4 and MgO single crystalline substrates to explore such behavior in thin film form. Atomic force microscopy indicates <1nm RMS surface roughness, and 2- and 4-circle x-ray diffraction confirms film epitaxy. Films on MgAl2O4 have a critical temperature Tc of up to 11.3K with a resistivity transition width of 0.25K, while films on MgO have lower Tc with broader transitions. Magnetization vs. magnetic field of a zero-field cooled sample shows Meissner shielding consistent with Type II superconductors. Such films can be used in spin-polarization measurements of complex oxide half-metallic thin films, as well as fundamental studies of the effect of epitaxial strain, microstructure, and cation disorder/substitution on the superconducting properties of LiTi2O4. [1] M. Lauer et al, Phys Rev B 69, 075117 (2004).

  3. Specific heat measurement set-up for quench condensed thin superconducting films

    NASA Astrophysics Data System (ADS)

    Poran, Shachaf; Molina-Ruiz, Manel; Gérardin, Anne; Frydman, Aviad; Bourgeois, Olivier

    2014-05-01

    We present a set-up designed for the measurement of specific heat of very thin or ultra-thin quench condensed superconducting films. In an ultra-high vacuum chamber, materials of interest can be thermally evaporated directly on a silicon membrane regulated in temperature from 1.4 K to 10 K. On this membrane, a heater and a thermometer are lithographically fabricated, allowing the measurement of heat capacity of the quench condensed layers. This apparatus permits the simultaneous thermal and electrical characterization of successively deposited layers in situ without exposing the deposited materials to room temperature or atmospheric conditions, both being irreversibly harmful to the samples. This system can be used to study specific heat signatures of phase transitions through the superconductor to insulator transition of quench condensed films.

  4. Hot carrier type exchange in inorganic electroluminescent thin films

    Microsoft Academic Search

    Katsu Tanaka; Shinji Okamoto

    2006-01-01

    The authors have observed the hot carrier type (holes or electrons) exchange in rare-earth-ion-activated strontium thiogallate (SrGa2S4) thin films by measuring the transient electroluminescent wave forms of the devices having a single insulating thin film. Measured wave forms revealed that the green electroluminescence of europium activated SrGa2S4 thin film occurs due to hot hole excitation. In contrast, the blue electroluminescence

  5. Overview and Challenges of Thin Film Solar Electric Technologies

    Microsoft Academic Search

    H. S. Ullal

    2008-01-01

    In this paper, we report on the significant progress made worldwide by thin-film solar cells, namely, amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium diselenide (CIGS). Thin-film photovoltaic (PV) technology status is also discussed in detail. In addition, R&D and technology challenges in all three areas are elucidated. The worldwide estimated projection for thin-film PV technology production capacity

  6. Overview and Challenges of Thin Film Solar Electric Technologies

    SciTech Connect

    Ullal, H. S.

    2008-12-01

    In this paper, we report on the significant progress made worldwide by thin-film solar cells, namely, amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium diselenide (CIGS). Thin-film photovoltaic (PV) technology status is also discussed in detail. In addition, R&D and technology challenges in all three areas are elucidated. The worldwide estimated projection for thin-film PV technology production capacity announcements are estimated at more than 5000 MW by 2010.

  7. A review of thin-film resonator technology

    Microsoft Academic Search

    K. M. Lakin

    2003-01-01

    Thin-film resonator technology has been under development for over 40 years as a means to reach higher frequencies than obtainable with conventional quartz-crystal technology. Using advances in microelectronic processing, thin films of piezoelectric materials are used to fabricate resonators and filters over a range of 500 MHz to 20 GHz. This article is a review of the thin-film resonator (TFR)

  8. Shape-related useful properties of nanostructured thin films

    NASA Astrophysics Data System (ADS)

    Suzuki, Motofumi

    2015-04-01

    The recent status of practical applications of obliquely deposited thin films is reviewed. Owing to the anisotropy in polarizability of elongated nanocolumns, obliquely deposited thin films in the form of assemblies of aligned nanocolumns show anisotropies in various properties, such as birefringence, dichroism, and magnetism. In addition, we introduce examples of practical applications: thin film waveplates, angular selective coatings, Au nanorod arrays for surface-enhanced Raman scattering, and low-reflectivity wire-grid polarizers.

  9. The CdTe Thin Film Solar Cell - AN Overview

    Microsoft Academic Search

    Dieter Bonnet

    1992-01-01

    The basic physical aspects of the CdTe-thin film solar cell in its various embodiments are reviewed. Deposition techniques are briefly described, results of present pilot-line production efforts and the future potential are discussed, which make the CdTe thin film solar cell a promising candidate for low cost and well-above 10% module-efficiency. A detailed costing model for thin film solar cells

  10. Recent progress in Si thin film technology for solar cells

    Microsoft Academic Search

    Yukinori Kuwano; Shoichi Nakano; Shinya Tsuda

    1991-01-01

    Progress in Si thin film technology 'specifically amorphous Si (a-Si) and polycrystalline Si (poly-Si) thin film' for solar cells is summarized here from fabrication method, material, and structural viewpoints. In addition to a-Si, primary results on poly-Si thin film research are discussed. Various applications for a-Si solar cells are mentioned, and consumer applications and a-Si solar cell photovoltaic systems are

  11. Electric Field Effects in Poled Polymer Thin Film Systems

    Microsoft Academic Search

    M. H. Ostrowski; H. S. Lackritz

    1996-01-01

    We have studied the effect of large magnitude, sub-breakdown electric fields on polymer thin film systems in order to improve poling efficiencies in polymer thin films for second order nonlinear optical applications. Electrochromic, dielectric relaxation, thermal pulse, and second harmonic generation measurements were performed on poly(methyl methacrylate) and polycarbonate thin films doped with Disperse Red 1 or 4-(dimethylamino)-4^'-nitrostilbene at various

  12. Microstructural evolution of sputtered phase segregated metal composite thin films

    Microsoft Academic Search

    Dana I. Filoti

    2010-01-01

    In this thesis, we present the first comparative study of crystallographic texture development in three different types of metal thin film composites: fully miscible (Au-Ag), slightly immiscible (Cu-Ag) and immiscible (Au-SiO 2). Texture development refers to the distribution of orientations of crystallites in polycrystalline thin films, and is an important part of the microstructure that determines thin film properties. A

  13. Overview of current bulk and thick film high temperature superconductor processing strategies

    SciTech Connect

    Ott, K.C.; Quinn, R.K.

    1990-01-01

    A review of processing strategies to prepare conductor-configured high temperature superconductors is presented along with a tabulation of recent results obtained using a variety of processing procedures to produce wires, tapes, monoliths, and thick films of high temperature superconducting material. 32 refs., 1 tab.

  14. Characterization of cosputtered tungsten carbide thin films

    SciTech Connect

    Kumar, C.V.; Barton, J.K.; Gould, I.R.; Turro, N.J.; VanHouten, J.

    1988-01-01

    Polycrystalline thin films of W-C were deposited on single-crystal Si(111) or SiO/sub 2/ substrates by r.f. planar magnetron cosputtering of graphite and tungsten targets. The reaction of these W-C films in the presence or absence of an additional bonding layer of titanium with silicon or SiO/sub 2/ substrates was studied in the temperature range from 500 to 800 C by a combination of backscattering spectrometry, scanning electron microscopy, x-ray diffraction, and sheet-resistivity measurements. Films of composition W43C57 are of the cubic WC1-x phase and have a room temperature resistivity of 100 micro ohms cm. On thermal annealing for 30 min in vacuum on silicon substrates, they form blisters above 700 C. Films of composition W73C25 are of the hexagonal alpha W/sub 2/C phase and have a room-temperature resistivity of 140 micro ohms cm. On silicon substrates, they are thermally stable up to 800 C annealing. WSi/sub 2/ is observed only above 800 C annealing. The sheet resistance at room temperature of films of either composition on SiO/sub 2/ is unchanged after annealing up to 800 C.

  15. Optical properties of epitaxial PLT thin films

    SciTech Connect

    Kim, Y.; Erbil, A. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Physics; Boatner, L.A. [Oak Ridge National Lab., TN (United States); Steingart, L. [Metricon Corp., Pennington, NJ (United States); Mensah, T.; Hiamang, S. [Clark Atlanta Univ., GA (United States). Dept. of Physics

    1996-01-01

    Metalorganic chemical vapor deposition was used to prepare epitaxial or highly oriented PLT (Pb{sub 1-x}La{sub x}TiO{sub 3}) thin films with x = 0.21-0.34. The growth of PLT films resulted in 3-D epitaxial heterostructures on a (100) surface of both MgO and KTaO{sub 3} substrates. The PLT film grown on a KTaO{sub 3} (100) substrate has a significantly lower minimum channeling yield compared to that grown on the MgO (100) substrate because of the smaller lattice mismatch associated with KTaO{sub 3}. Thickness and refractive indices at 435-1523 nm were measured by prism coupling. Measured film thickness of 570 nm was in good agreement with that obtained from RBS. Refractive index of the PLT film is smaller than that of PbTiO{sub 3}, and its difference at {lambda} = 632.8 nm is about 2.5%. Dispersion of the refractive index was well fitted by a Sellmeier dispersion formula.

  16. Review of the fundamentals of thin-film growth.

    PubMed

    Kaiser, Norbert

    2002-06-01

    The properties of a thin film of a given material depend on the film's real structure. The real structure is defined as the link between a thin film's deposition parameters and its properties. To facilitate engineering the properties of a thin film by manipulating its real structure, thin-film formation is reviewed as a process starting with nucleation followed by coalescence and subsequent thickness growth, all stages of which can be influenced by deposition parameters. The focus in this review is on dielectric and metallic films and their optical properties. In contrast to optoelectronics all these film growth possibilities for the engineering of novel optical films with extraordinary properties are just beginning to be used. PMID:12064380

  17. Chemical vapor deposition of organosilicon and sacrificial polymer thin films

    E-print Network

    Casserly, Thomas Bryan

    2005-01-01

    Chemical vapor deposition (CVD) produced films for a wide array of applications from a variety of organosilicon and organic precursors. The structure and properties of thin films were controlled by varying processing ...

  18. Uncooled thin film pyroelectric IR detector with aerogel thermal isolation

    DOEpatents

    Ruffner, Judith A. (Albuquerque, NM); Bullington, Jeff A. (Albuquerque, NM); Clem, Paul G. (Albuquerque, NM); Warren, William L. (Albuquerque, NM); Brinker, C. Jeffrey (Albuquerque, NM); Tuttle, Bruce A. (Albuquerque, NM); Schwartz, Robert W. (Seneca, SC)

    1999-01-01

    A monolithic infrared detector structure which allows integration of pyroelectric thin films atop low thermal conductivity aerogel thin films. The structure comprises, from bottom to top, a substrate, an aerogel insulating layer, a lower electrode, a pyroelectric layer, and an upper electrode layer capped by a blacking layer. The aerogel can offer thermal conductivity less than that of air, while providing a much stronger monolithic alternative to cantilevered or suspended air-gap structures for pyroelectric thin film pixel arrays. Pb(Zr.sub.0.4 Ti.sub.0.6)O.sub.3 thin films deposited on these structures displayed viable pyroelectric properties, while processed at 550.degree. C.

  19. Non-local thin films in Casimir force calculations

    E-print Network

    R. Esquivel; V. Svetovoy

    2005-06-01

    he Casimir force is calculated between plates with thin metallic coating. Thin films are described with spatially dispersive (nonlocal) dielectric functions. For thin films the nonlocal effects are more relevant than for half-spaces. However, it is shown that even for film thickness smaller than the mean free path for electrons, the difference between local and nonlocal calculations of the Casimir force is of the order of a few tenths of a percent. Thus the local description of thin metallic films is adequate within the current experimental precision and range of separations.

  20. Thin-Film Photovoltaics: Status and Applications to Space Power

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Hepp, Aloysius F.

    1991-01-01

    The potential applications of thin film polycrystalline and amorphous cells for space are discussed. There have been great advances in thin film solar cells for terrestrial applications; transfer of this technology to space applications could result in ultra low weight solar arrays with potentially large gains in specific power. Recent advances in thin film solar cells are reviewed, including polycrystalline copper iridium selenide and related I-III-VI2 compounds, polycrystalline cadmium telluride and related II-VI compounds, and amorphous silicon alloys. The possibility of thin film multi bandgap cascade solar cells is discussed.

  1. Applications of thin-film photovoltaics for space

    NASA Astrophysics Data System (ADS)

    Landis, Geoffrey A.; Hepp, Aloysius F.

    The authors discuss the potential applications of thin-film polycrystalline and amorphous cells for space. There have been great advances in thin-film solar cells for terrestrial applications. Transfer of this technology to space applications could result in ultra low-weight solar arrays with potentially large gains in specific power. Recent advances in thin-film solar cells are reviewed, including polycrystalline copper indium selenide and related I-III-VI2 compounds, polycrystalline cadmium telluride and related II-VI compounds, and amorphous silicon arrays. The possibility of using thin-film multi-bandgap cascade solar cells is discussed.

  2. Polycrystalline Thin-Film Photovoltaic Technologies: Progress and Technical Issues

    Microsoft Academic Search

    Harin S. Ullal

    2004-01-01

    Polycrystalline thin-film materials based on copper indium diselenide (CuInSe2, CIS) and cadmium telluride (CdTe) are promising thin-film solar cells for various power and specialty applications. Impressive results have been obtained in the past few years for both thin-film copper indium gallium diselenide (CIGS) solar cells and thin-film CdTe solar cells. NCPV\\/NREL scientists have achieved world-record, total-area efficiencies of 19.3% for

  3. Progress on thin-film sensors for space propulsion technology

    NASA Astrophysics Data System (ADS)

    Kim, Walter S.

    The objective is to develop thin-film thermocouples for Space Shuttle Main Engine (SSME) components. Thin-film thermocouples have been developed for aircraft gas turbine engines and are in use for temperature measurement on turbine blades to 1800 F. The technology established for aircraft gas turbine engines will be adapted to the materials and environment encountered in the SSME. Specific goals are to expand the existing in-house thin-film sensor technology and to test the survivability and durability of thin-film sensors in the SSME environment.

  4. Optical properties of polygonal chiral sculptured thin films

    E-print Network

    Babaei, Ferydon

    2012-01-01

    The optical rotation and selective transmission spectrum of polygonal chiral sculptured thin films using transfer matrix method have been calculated. The results of optical modeling showed that optical characteristics polygonal chiral sculptured thin films are the same as chiral sculptured thin films in lower angular rotations. In higher angular rotations appear two circular reflection bands. The primary at shorter wavelengths reflects LCP light and the secondary at longer wavelengths reflects RCP light. By adding twist and layer defects in the morphology of polygonal chiral sculptured thin films, the creation of spectral holes in two Bragg regimes, have been reported.

  5. Indium selenide thin film preparation by sol–gel technique

    Microsoft Academic Search

    Ibrahim H. Mutlu; Maharram Z. Zarbaliyev; Ferhat Aslan

    2007-01-01

    s  Preparation and characterization of In–Se compound thin films prepared by sol–gel methods on glass substrate have been studied.\\u000a X-ray diffraction analyses and optical transmission spectrum of In–Se compound thin film samples show that the fabricated\\u000a sol–gel In–Se thin films features formed mainly as an In2Se3 crystal structure. From transmission spectra of In–Se thin films band gap energy were estimated approximately

  6. Dye-Sensitization Of Nanocrystalline ZnO Thin Films

    SciTech Connect

    Ajimsha, R. S.; Tyagi, M.; Das, A. K.; Misra, P.; Kukreja, L. M. [Laser Materials Processing Division, Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India)

    2010-12-01

    Nannocrystalline and nanoporus thin films of ZnO were synthesized on glass substrates by using wet chemical drop casting method. X-ray diffraction measurements on these samples confirmed the formation of ZnO nanocrystallites in hexagonal wurtzite phase with mean size of {approx}20 nm. Photo sensitization of these nanostructured ZnO thin films was carried out using three types of dyes Rhodamine 6 G, Chlorophyll and cocktail of Rhodamine 6 G and Chlorophyll in 1:1 ratio. Dye sensitized ZnO thin films showed enhanced optical absorption in visible spectral region compared to the pristine ZnO thin films.

  7. Structural characterization of impurified zinc oxide thin films

    NASA Astrophysics Data System (ADS)

    Trinca, L. M.; Galca, A. C.; Stancu, V.; Chirila, C.; Pintilie, L.

    2014-11-01

    Europium doped zinc oxide (Eu:ZnO) thin films have been obtained by pulsed laser deposition (PLD). 002 textured thin films were achieved on glass and silicon substrates, while hetero-epilayers and homo-epilayers have been attained on single crystal SrTiO3 and ZnO, respectively. X-ray Diffraction (XRD) was employed to characterize the Eu:ZnO thin films. Extended XRD studies confirmed the different thin film structural properties as function of chosen substrates.

  8. Search for new materials: phase spread alloy thin film fabrication and characterization

    NASA Astrophysics Data System (ADS)

    Marsh, Moses; Basaran, Ali; de La Venta, Jose; Khatib, Omar; Shpyrko, Oleg; Basov, Dmitri; Schuller, Ivan

    2012-02-01

    We use the phase spread alloy (PSA) method of fabricating compositionally heterogeneous thin films as an efficient way to produce and screen new, interesting materials (e.g. superconductors, magnetoresistive compounds, etc.). This method uses co-sputtering to deposit material with smoothly varying element concentration across a substrate. Both local and non-local probes are used to verify the composition of the sample. Using the La-Si-C system as an example, we perform x-ray fluorescence from a synchrotron source, x-ray diffraction from a lab source, atomic force microscopy, and infrared spectroscopy on one sample to verify the presence of different phases and their properties.

  9. Role of asphaltenes in stabilizing thin liquid emulsion films.

    PubMed

    Tchoukov, Plamen; Yang, Fan; Xu, Zhenghe; Dabros, Tadeusz; Czarnecki, Jan; Sjöblom, Johan

    2014-03-25

    Drainage kinetics, thickness, and stability of water-in-oil thin liquid emulsion films obtained from asphaltenes, heavy oil (bitumen), and deasphalted heavy oil (maltenes) diluted in toluene are studied. The results show that asphaltenes stabilize thin organic liquid films at much lower concentrations than maltenes and bitumen. The drainage of thin organic liquid films containing asphaltenes is significantly slower than the drainage of the films containing maltenes and bitumen. The films stabilized by asphaltenes are much thicker (40-90 nm) than those stabilized by maltenes (?10 nm). Such significant variation in the film properties points to different stabilization mechanisms of thin organic liquid films. Apparent aging effects, including gradual increase of film thickness, rigidity of oil/water interface, and formation of submicrometer size aggregates, were observed for thin organic liquid films containing asphaltenes. No aging effects were observed for films containing maltenes and bitumen in toluene. The increasing stability and lower drainage dynamics of asphaltene-containing thin liquid films are attributed to specific ability of asphaltenes to self-assemble and form 3D network in the film. The characteristic length of stable films is well beyond the size of single asphaltene molecules, nanoaggregates, or even clusters of nanoaggregates reported in the literature. Buildup of such 3D structure modifies the rheological properties of the liquid film to be non-Newtonian with yield stress (gel like). Formation of such network structure appears to be responsible for the slower drainage of thin asphaltenes in toluene liquid films. The yield stress of liquid film as small as ?10(-2) Pa is sufficient to stop the drainage before the film reaches the critical thickness at which film rupture occurs. PMID:24564447

  10. Indium and tin oxide multilayered thin films as gas sensors based on reactive pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Marotta, Veronica; Orlando, Stefano; Parisi, Giovanni P.; Giardini-Guidoni, Anna

    2000-02-01

    Pulsed laser ablation is a very interesting method to deposit thin films of several materials and compounds as oxides, nitrides, insulators, semi- and super-conductors. Indium and In Oxide polycrystalline thin films have been gown on silicon substrates by reactive pulsed laser deposition from two metallic targets of indium and Tin by a multilayered deposition, both in presence of oxygen, using a frequency doubled Nd:YAG laser. These In2O3, SnO2 thin films find valid application as antistatic coatings, transparent resistive heaters, electrical electrodes for flat panel display and electrochromic device.s A comparison has been performed, among Indium Oxide, Tin Oxide, and multilayers of Indium and Tin Oxides, to evaluate their use as gas sensor devices. The influence of the physical parameters such as the substrate temperature, the laser energy, and the oxygen pressure in the deposition chamber has been investigated. The plume has been monitored by fast photography. The characterization of the films has been performed by X-Ray Diffraction, showing a preferential orientation. A four-contact probe shows that our films exhibit an increase in resistivity when exposed to NO.

  11. a Study of Transparent Zinc Oxide Thin Films

    Microsoft Academic Search

    Yi. Qu

    1993-01-01

    The structural, electrical, and optical properties of ion-beam-sputtered undoped and Al-doped ZnO thin films have been studied. Undoped films were studied as a function of film thickness and deposition temperature and the Al -doped films were studied as a function of film thickness, deposition temperature, and Al doping levels. The microstructures of the films were characterized using X-ray diffraction and

  12. CCMR: Synthesis of Nanoporous Gold Thin Films

    NSDL National Science Digital Library

    Thiel, Andrew

    2005-08-17

    Starting with a gold alloy, it is possible to selectively etch away the non-gold element and obtain a tortuous porous network within the gold with pore widths ranging from just 20-4nm. The vast amount of void space makes for large surface areas of approximately 2 m²/g. This new material has found use in such applications as filters, biosensors, chemical catalysts, and ultra-capacitors. Through annealing, the size of these pores can be modified to fit the need of its particular application. Previous research has been done here at Cornell on nanoporous gold in the form of bulk films with of 200?m. However, the behavior of thin films of this material of just 200nm in thickness has not yet been studied extensively. The goal of this project was to come up with a way to create nanoporous gold thin films and to measure the effects of pore coarsening during annealing and the amount of silver remaining in the sample during the etching procedure.

  13. An overview of ferroelectric thin film technology

    SciTech Connect

    Tuttle, B.A.; Voigt, J.A.; Al-Shareef, H.N.; Dimos, D. [Sandia National Labs., Albuquerque, NM (United States)

    1996-12-31

    There has recently been an explosion of technical interest in ferroelectric (FE) thin films because of the large number of diverse, near term applications for which these films are the primary media. These applications include piezoelectric micromotors, pyrolelectric detectors, nonvolatile memories, and high frequency filters. Solution deposited Pb(Zr,Ti)O{sub 3} thin films will be used as a model to demonstrate how solution synthesis and underlying electrode technology can be used to control microstructure, crystallite orientation and 90{degrees} domain assemblages. These nanoscale features determine properties, such as, remanent polarization, dielectric constant and piezoelectric coefficients that substantially impact device performance. Relationships among solution synthesis route, Zr to Ti stoichiometry and associated thermal processing and their effect on phase assemblage and resultant properties is presented. While electrode surface nanotopography is a primary factor that controls formation of undesirable second phase assemblages and perovskite is a primary factor that controls formation of undesirable second phase assemblages and perovskite grain size, transformation stress and grain size substantially determine 90{degrees} domain orientations.

  14. PZT Thin Film Piezoelectric Traveling Wave Motor

    NASA Technical Reports Server (NTRS)

    Shen, Dexin; Zhang, Baoan; Yang, Genqing; Jiao, Jiwei; Lu, Jianguo; Wang, Weiyuan

    1995-01-01

    With the development of micro-electro-mechanical systems (MEMS), its various applications are attracting more and more attention. Among MEMS, micro motors, electrostatic and electromagnetic, are the typical and important ones. As an alternative approach, the piezoelectric traveling wave micro motor, based on thin film material and integrated circuit technologies, circumvents many of the drawbacks of the above mentioned two types of motors and displays distinct advantages. In this paper we report on a lead-zirconate-titanate (PZT) piezoelectric thin film traveling wave motor. The PZT film with a thickness of 150 micrometers and a diameter of 8 mm was first deposited onto a metal substrate as the stator material. Then, eight sections were patterned to form the stator electrodes. The rotor had an 8 kHz frequency power supply. The rotation speed of the motor is 100 rpm. The relationship of the friction between the stator and the rotor and the structure of the rotor on rotation were also studied.

  15. Electrosynthesis of the molybdenum disulphide thin films and characterization

    Microsoft Academic Search

    R. S Patil

    1999-01-01

    Thin films of molybdenum disulphide have been prepared by electrodeposition from an aqueous bath by using molybdenum trioxide and sodium thiosulphate as Mo+ ion and S?2 ion sources, respectively. The films deposited onto stainless steel and fluorine doped tin oxide (FTO) glass substrates were adherent to the substrate. X-ray diffraction studies show that films are polycrystalline. SEM shows films are

  16. Interpretation of stresses in thin films from wafer shape

    Microsoft Academic Search

    Anton F. Jachim

    2001-01-01

    In general, thin films deposited during semiconductor manufacturing exhibit intrinsic stress. If these stresses are not controlled, they can lead to failure of electronic devices by a variety of mechanisms. To some extent, film stress can be controlled by deposition process variation or annealing. But, in order to accurately control film stress, it must be accurately measured. Most film stress

  17. In situ deformation of thin films on substrates

    Microsoft Academic Search

    Marc Legros; Martiane Cabié; Daniel S. Gianola

    2009-01-01

    Metallic thin-film plasticity has been widely studied by using the difference between the coefficients of thermal expansion of the film and the underlying substrate to induce stress. This approach is commonly known as the wafer curvature technique, based on the Stoney equation, which has shown that thinner films have higher yield stresses. The linear increase of the film strength as

  18. Ambient temperature growth of nanocrystalline titanium dioxide thin films

    Microsoft Academic Search

    D. Pamu; M. Ghanashyam Krishna; K. C. James Raju; Anil K. Bhatnagar

    2005-01-01

    Nanocrystalline titania thin films have been deposited at ambient temperature by Dc magnetron sputtering. The crystallite size in the films varies between 25 and 50 nm as calculated from the X-ray diffraction patterns and is dependent on both oxygen pressure as well as thickness of the films. Significantly even at 100% oxygen in the sputtering gas, films of thickness of

  19. Ambient temperature growth of nanocrystalline titanium dioxide thin films

    Microsoft Academic Search

    D. Pamu; M. Ghanashyam Krishna; K. C. James Raju; Anil K. Bhatnagar

    2005-01-01

    Nanocrystalline titania thin films have been deposited at ambient temperature by Dc magnetron sputtering. The crystallite size in the films varies between 25 and 50nm as calculated from the X-ray diffraction patterns and is dependent on both oxygen pressure as well as thickness of the films. Significantly even at 100% oxygen in the sputtering gas, films of thickness of the

  20. Studies on the electrical conduction in silver telluride thin films

    Microsoft Academic Search

    P. Gnanadurai; N. Soundararajan; C. E. Sooriamoorthi

    2003-01-01

    The temperature dependence of the electrical resistance of unannealed and annealed silver telluride thin films of different thickness between 30 and 110 nm, prepared by thermal evaporation at a pressure of 2 × 10-5 mbar, has been studied. The films are polycrystalline. It is found that metastable defects influence the phase transition in unannealed films. The annealed films undergo a

  1. Integrated CNTs thin film for MEMS mechanical sensors

    Microsoft Academic Search

    Van Thanh Dau; Takeo Yamada; Dzung Viet Dao; Bui Thanh Tung; Kenji Hata; Susumu Sugiyama

    2010-01-01

    This paper reports the top-down fabrication of CNTs thin film on MEMS structure, and characterization of piezoresistive coefficients of aligned single wall carbon nanotube (SWNT) forest film. The film was synthesized by water-assisted chemical vapor deposition (CVD), a process known as “super growth”. CNTs film was condensed, manually maneuvered and conveniently patterned by EB lithography to form desirable shapes. The

  2. Growth and characterisation of electrodeposited ZnO thin films

    Microsoft Academic Search

    J. S. Wellings; N. B. Chaure; S. N. Heavens; I. M. Dharmadasa

    2008-01-01

    The electrochemical method has been used to deposit zinc oxide (ZnO) thin films from aqueous zinc nitrate solution at 80 °C onto fluorine doped tin oxide (FTO) coated glass substrates. ZnO thin films were grown between ? 0.900 and ? 1.025 V vs Ag\\/AgCl as established by voltammogram. Characterisation of ZnO films was carried out for both as-deposited and annealed films in order to

  3. Microstructure–electrical conductivity relationships in nanocrystalline ceria thin films

    Microsoft Academic Search

    Toshio Suzuki; Igor Kosacki; Harlan U Anderson

    2002-01-01

    A study of nanocrystalline oxide thin film processing and influence of microstructure on the electrical properties of nanocrystalline Gd3+-doped CeO2 thin films was reported. Nanocrystalline films on sapphire substrate were prepared using a polymeric precursor spin coating technique. The grain size of these films depends upon the annealing temperatures and the dopant content, where higher content of dopant realized smaller

  4. Magnetical studies on thin films of iron oxides

    Microsoft Academic Search

    Jaime Osorio; Juan Uribe; Cesar Barrero; Doris Girata; Alvaro Morales; Axel Hoffmann; Ramon Gancedo

    2008-01-01

    We have grown hematite (alpha-Fe2O3) thin films on stainless steel and silicon dioxide (SiO2) substrates and magnetite (Fe3O4) thin films on silicon substrates by RF magnetron sputtering process. Conversion Electron Mössbauer (CEM) spectra of these films exhibit hyperfine parameter values which are characteristic of these iron oxides. Magnetization measurements parallel to the plane of the film as a function of

  5. Anomalous Hall effect in NiPt thin films

    Microsoft Academic Search

    T. Golod; A. Rydh; V. M. Krasnov

    2011-01-01

    We study Hall effect in sputtered NixPt1-x thin films with different Ni concentrations. Temperature, magnetic field and angular dependencies are analyzed and the phase diagram of NiPt thin films is obtained. It is found that films with sub-critical Ni concentration exhibit cluster-glass behavior at low temperatures with a perpendicular magnetic anisotropy below the freezing temperature. Films with over-critical Ni concentration

  6. Electronic evidence of an insulator–superconductor crossover in single-layer FeSe/SrTiO3 films

    PubMed Central

    He, Junfeng; Liu, Xu; Zhang, Wenhao; Zhao, Lin; Liu, Defa; He, Shaolong; Mou, Daixiang; Li, Fangsen; Tang, Chenjia; Li, Zhi; Wang, Lili; Peng, Yingying; Liu, Yan; Chen, Chaoyu; Yu, Li; Liu, Guodong; Dong, Xiaoli; Zhang, Jun; Chen, Chuangtian; Xu, Zuyan; Chen, Xi; Ma, Xucun; Xue, Qikun; Zhou, X. J.

    2014-01-01

    In high-temperature cuprate superconductors, it is now generally agreed that superconductivity is realized by doping an antiferromagnetic Mott (charge transfer) insulator. The doping-induced insulator-to-superconductor transition has been widely observed in cuprates, which provides important information for understanding the superconductivity mechanism. In the iron-based superconductors, however, the parent compound is mostly antiferromagnetic bad metal, raising a debate on whether an appropriate starting point should go with an itinerant picture or a localized picture. No evidence of doping-induced insulator–superconductor transition (or crossover) has been reported in the iron-based compounds so far. Here, we report an electronic evidence of an insulator–superconductor crossover observed in the single-layer FeSe film grown on a SrTiO3 substrate. By taking angle-resolved photoemission measurements on the electronic structure and energy gap, we have identified a clear evolution of an insulator to a superconductor with increasing carrier concentration. In particular, the insulator–superconductor crossover in FeSe/SrTiO3 film exhibits similar behaviors to that observed in the cuprate superconductors. Our results suggest that the observed insulator–superconductor crossover may be associated with the two-dimensionality that enhances electron localization or correlation. The reduced dimensionality and the interfacial effect provide a new pathway in searching for new phenomena and novel superconductors with a high transition temperature. PMID:25502774

  7. Polycrystalline-thin-film thermophotovoltaic cells

    NASA Astrophysics Data System (ADS)

    Dhere, Neelkanth G.

    1996-02-01

    Thermophotovoltaic (TPV) cells convert thermal energy to electricity. Modularity, portability, silent operation, absence of moving parts, reduced air pollution, rapid start-up, high power densities, potentially high conversion efficiencies, choice of a wide range of heat sources employing fossil fuels, biomass, and even solar radiation are key advantages of TPV cells in comparison with fuel cells, thermionic and thermoelectric convertors, and heat engines. The potential applications of TPV systems include: remote electricity supplies, transportation, co-generation, electric-grid independent appliances, and space, aerospace, and military power applications. The range of bandgaps for achieving high conversion efficiencies using low temperature (1000-2000 K) black-body or selective radiators is in the 0.5-0.75 eV range. Present high efficiency convertors are based on single crystalline materials such as In1-xGaxAs, GaSb, and Ga1-xInxSb. Several polycrystalline thin films such as Hg1-xCdxTe, Sn1-xCd2xTe2, and Pb1-xCdxTe, etc., have great potential for economic large-scale applications. A small fraction of the high concentration of charge carriers generated at high fluences effectively saturates the large density of defects in polycrystalline thin films. Photovoltaic conversion efficiencies of polycrystalline thin films and PV solar cells are comparable to single crystalline Si solar cells, e.g., 17.1% for CuIn1-xGaxSe2 and 15.8% for CdTe. The best recombination-state density Nt is in the range of 10-15-10-16 cm-3 acceptable for TPV applications. Higher efficiencies may be achieved because of the higher fluences, possibility of bandgap tailoring, and use of selective emitters such as rare earth oxides (erbia, holmia, yttria) and rare earth-yttrium aluminium garnets. As compared to higher bandgap semiconductors such as CdTe, it is easier to dope the lower bandgap semiconductors. TPV cell development can benefit from the more mature PV solar cell and opto-electronic (infrared detectors, lasers, and optical communications) technologies. Low bandgaps and larger fluences employed in TPV cells result in very high current densities which make it difficult to collect the current effectively. Techniques for laser and mechanical scribing, integral interconnection, and multi-junction tandem structures which have been fairly well developed for thin-film PV solar cells could be further refined for enhancing the voltages from TPV modules. Thin-film TPV cells may be deposited on metals or back-surface reflectors. Spectral control elements such as indium-tin oxide or tin oxide may be deposited directly on the TPV convertor. It would be possible to reduce the cost of TPV technologies based on single-crystal materials being developed at present to the range of US 2-5 per watt so as to be competitive in small to medium size commercial applications. However, a further cost reduction to the range of US ¢ 35- 1 per watt to reach the more competitive large-scale residential, consumer, and hybrid-electric car markets would be possible only with the polycrystalline-thin film TPV cells.

  8. Pulsed Laser Deposition of Epitaxial Topological Insulator Thin Films: Bi2Te3 and Bi2Te2Se

    NASA Astrophysics Data System (ADS)

    Zhang, Shixiong; Yan, Li; Qi, Jingbo; Zhuo, Mujin; Wang, Yongqiang; Prasankumar, Rohit P.; Jia, Quanxi; Picraux, S. Tom

    2012-02-01

    While high quality epitaxial thin films of topological insulators have been achieved by molecular beam epitaxy, there has been little progress using other thin film growth techniques. Here, we report the growth of high quality epitaxial Bi2Te3 and Bi2Te2Se thin films on silicon (111) and YSZ (111) substrates by pulsed laser deposition (PLD). Systematic structural characterization of the films using x-ray diffraction and transmission electron microscopy has demonstrated that a low laser pulse rate is the key to achieving high quality epitaxial films. Rutherford backscattering spectrometry measurements suggest that the film composition is strongly influenced by the growth temperature and background gas pressure. The electrical transport properties of the films grown at the optimal conditions will also be discussed. Since PLD is an excellent tool to grow a variety of functional oxides, including multiferroics, magnetic semiconductors and high temperature superconductors, the growth of epitaxial topological insulator thin films by the same technique paves the way to synthesize multi-layered heterostructures of the above materials and search for novel physics arising from the resulting interfacial couplings.

  9. Texture development in BPSCCO superconductors

    SciTech Connect

    Mani, T.V.; Damodaran, A.D.; Warrier, K.G. [CSIR, Trivandrum (India)

    1995-09-01

    After the discovery of bismuth-based superconductors, many attempts were made to develop high-density, sintered Bi-Pb-Sr-Ca-Cu-O (BPSCCO) ceramics having high current density (J{sub c}). Small coherence length, grain-boundary weak links and anisotropy of the high-critical-temperature (T{sub c}) cuprate grains of these superconductors caused lower J{sub c} values, even in epitaxially grown thin films. This report relates to an integrated approach for obtaining oriented microstructure in BPSCCO superconductor by combining two processing steps: viscous pressing (presintering process, PSP) and zone-melting refining (postsintering treatments, PST).

  10. Nanostructured Thin Film Electrolyte for Thin Film Solid Oxide Fuel Cells 

    E-print Network

    Cho, Sungmee

    2012-10-19

    thickness) and an yttria-stabilized ZrO2 (YSZ) layer with various thicknesses (~330 nm, ~440 nm, and ~1 micrometer) are achieved by a pulsed laser deposition (PLD) technique for thin film solid oxide fuel cells (TFSOFCs). One effective approach...

  11. Rechargeable thin-film electrochemical generator

    DOEpatents

    Rouillard, Roger (Beloeil, CA); Domroese, Michael K. (South St. Paul, MN); Hoffman, Joseph A. (Minneapolis, MN); Lindeman, David D. (Hudson, WI); Noel, Joseph-Robert-Gaetan (St-Hubert, CA); Radewald, Vern E. (Austin, TX); Ranger, Michel (Lachine, CA); Sudano, Anthony (Laval, CA); Trice, Jennifer L. (Eagan, MN); Turgeon, Thomas A. (Fridley, MN)

    2000-09-15

    An improved electrochemical generator is disclosed. The electrochemical generator includes a thin-film electrochemical cell which is maintained in a state of compression through use of an internal or an external pressure apparatus. A thermal conductor, which is connected to at least one of the positive or negative contacts of the cell, conducts current into and out of the cell and also conducts thermal energy between the cell and thermally conductive, electrically resistive material disposed on a vessel wall adjacent the conductor. The thermally conductive, electrically resistive material may include an anodized coating or a thin sheet of a plastic, mineral-based material or conductive polymer material. The thermal conductor is fabricated to include a resilient portion which expands and contracts to maintain mechanical contact between the cell and the thermally conductive material in the presence of relative movement between the cell and the wall structure. The electrochemical generator may be disposed in a hermetically sealed housing.

  12. Process for making dense thin films

    DOEpatents

    Jacobson, Craig P.; Visco, Steven J.; DeJonghe, Lutgard C.

    2005-07-26

    Provided are low-cost, mechanically strong, highly electronically conductive porous substrates and associated structures for solid-state electrochemical devices, techniques for forming these structures, and devices incorporating the structures. The invention provides solid state electrochemical device substrates of novel composition and techniques for forming thin electrode/membrane/electrolyte coatings on the novel or more conventional substrates. In particular, in one embodiment the invention provides techniques for firing of device substrate to form densified electrolyte/membrane films 5 to 20 microns thick. In another embodiment, densified electrolyte/membrane films 5 to 20 microns thick may be formed on a pre-sintered substrate by a constrained sintering process. In some cases, the substrate may be a porous metal, alloy, or non-nickel cermet incorporating one or more of the transition metals Cr, Fe, Cu and Ag, or alloys thereof.

  13. Low cost thin film chalcopyrite solar cells

    NASA Astrophysics Data System (ADS)

    Kapur, Vijay K.; Basol, Bulent M.; Tseng, Eric S.

    A new low-cost process for the production of thin-film chalcopyrite solar cells of the type CuInSe2/Cds is reported. The CuInSe2 films were prepared utilizing electroplating techniques, and solar cells with 1.0-sq cm area and over 7 percent efficiency (without the antireflection coating) were fabricated. Correcting for the shading and the reflection losses, these devices can be projected to be about 10.0 percent efficient. Electroplating methods were also used for the preparation of absorber materials of varying compositions, such as CuIn(1-x)Ga(x)Se2. These materials are being investigated to achieve bandgap values approaching 1.5 eV.

  14. Low temperature OMCVD of thin rhodium films

    SciTech Connect

    Laia, J.R.; Sattelberger, A.P.; Smith, D.C. (Los Alamos National Lab., NM (United States)); DeSantis, J.C. (Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering)

    1992-01-01

    Thin, highly reflective rhodium films with metal compositions greater than 98% (elemental weight percentage) have been deposited by chemical vapor deposition using Rh(allyl){sub 3} (allyl = {eta}{sup 3}-C{sub 3}H{sub 5}) in the presence of a hydrogen plasma. Uniform, crystalline films that adhere well to several types of substrates result from depositions at temperatures as low as 150{degrees}C. Depositions using H{sub 2} (no plasma), or an argon plasma yields material that is amorphous, contains a significant amount (>14%) of residual carbon, and has a dramatically slower growth rate. The composition of these materials does not vary significantly from that of the materials obtained from the in vacuo thermal deposition with Rh(allyl){sub 3}. 23 refs.

  15. Laser deposition and laser modification of high-temperature superconducting thin films

    SciTech Connect

    Dye, R.C.; Foltyn, S.R.; Nogar, N.S.; Wu, X.D.; Peterson, E.J.; Muenchausen, R.E.

    1991-01-01

    Applications of high-temperature superconductors (HTSC) may require epitaxial films with {Tc}{ge}77 K, and J{sub c}{ge}10{sup 6} A/cm{sup 2}. In situ pulsed laser deposition (PLD) is suitable for fabrication of such films. We report parametric studies on the effect of laser and processing parameters on the crystallinity, epitaxy and electrical properties of laser-deposited HTSC thin films. In addition, several laser-based processes were used to modify the electrical properties ({Tc} and J{sub c}) of PLD thin films. A direct-write laser heating (1.06 {mu}m at {approx}0.5 kW/cm{sup 2} for {approx}5 min) process in an oxygen atmosphere at {approx}590 Torr was shown to selectivity regenerate high-{Tc} material in microscopic domains from films that were partially deoxygenated. In separate work, electrical responses and crystallinity of HTSC films were measured as a function of excimer laser exposure using fluences in the range 20--150 mJ/cm{sup 2}. The critical current and boundary layer could be modified with a high degree of accuracy. 17 refs., 4 figs.

  16. Chemical route to ferroelectric thin film capacitors

    Microsoft Academic Search

    J. P Mercurio; J. H Yi; P Thomas; M Manier

    1999-01-01

    For the first time the fabrication of ferroelectric SrBi2(Ta,Nb)2O9 thin film capacitors with RuO2 electrodes is conducted using a full chemical route. SrBi2(Ta,Nb)2O9 sols were obtained from niobium and tantalum ethoxides mixed with bismuth and strontium 2-ethylhexanoates. RuO2 sols were prepared by dissolving an aqueous solution of ruthenium nitrosylnitrate into 2-methoxyethanol. Capacitors were fabricated by spin coating the precursor solutions

  17. Electrical, morphological and structural properties of RF magnetron sputtered Mo thin films for application in thin film photovoltaic solar cells

    Microsoft Academic Search

    Guillaume ZoppiNeil; Neil S. Beattie; Jonathan D. Major; Robert W. Miles; Ian Forbes

    2011-01-01

    Molybdenum (Mo) thin films were deposited using radio frequency magnetron sputtering, for application as a metal back contact\\u000a material in “substrate configuration” thin film solar cells. The variations of the electrical, morphological, and structural\\u000a properties of the deposited films with sputtering pressure, sputtering power and post-deposition annealing were determined.\\u000a The electrical conductivity of the Mo films was found to increase

  18. Sputtered Thallium-Barium Superconducting Thin Films

    NASA Astrophysics Data System (ADS)

    Wu, Changyao

    Thin films, a necessary form of materials for most sensors and electronic applications, of Tl-Ba-Ca-Cu -O have been studied. The samples were prepared by the precursor method. Precursor films of Ba-Ca-Cu-O were first deposited on the single crystal substrates of MgO, LaAlO _3, and SrTiO_3 by rf-magnetron sputtering. The following heat-treatment facilitated the incorporation of thallium into the precursor films and proper phase formation. Processing variables were systematically studied and the resulting films were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Superconducting microbridges patterned by photolithography and wet chemical etching were used for R-T and I-V characteristics measurements. The resistive broadening of superconducting transition under magnetic fields was discussed in the framework of Anderson -Kim flux-creep theory. The activation energy for the flux -creep appears to be of functional form rm U_{o}~(1-T/ rm T_{c})/B^{1/2}. .

  19. Electrodeposited CuInSe2 Thin Film Junctions

    NASA Technical Reports Server (NTRS)

    Raffaelle, R. P.; Mantovani, J. G.; Bailey, S. G.; Hepp, A. F.; Gordon, E. M.; Haraway, R.

    1997-01-01

    We have investigated thin films and junctions based on copper indium diselenide (CIS) which have been grown by electrochemical deposition. CIS is a leading candidate for use in polycrystalline thin film photovoltaic solar cells. Electrodeposition is a cost-effective method for producing thin-film CIS. We have produced both p and n type CIS thin films from the same aqueous solution by simply varying the deposition potential. A CIS pn junction was deposited using a step-function potential. Stoichiometry of the single layer films was determined by energy dispersive spectroscopy. Carrier densities of these films increased with deviation from stoichiometry, as determined by the capacitance versus voltage dependence of Schottky contacts. Optical bandgaps for the single layer films as determined by transmission spectroscopy were also found to increase with deviation from stoichiometry. Rectifying current versus voltage characteristics were demonstrated for the Schottky barriers and for the pn junction.

  20. Organic thin films. Rational synthesis of organic thin films with exceptional long-range structural integrity.

    PubMed

    Seiki, Noriya; Shoji, Yoshiaki; Kajitani, Takashi; Ishiwari, Fumitaka; Kosaka, Atsuko; Hikima, Takaaki; Takata, Masaki; Someya, Takao; Fukushima, Takanori

    2015-06-01

    Highly oriented, domain-boundary-free organic thin films could find use in various high-performance organic materials and devices. However, even with state-of-the-art supramolecular chemistry, it is difficult to construct organic thin films with structural integrity in a size regime beyond the micrometer length scale. We show that a space-filling design, relying on the two-dimensional (2D) nested hexagonal packing of a particular type of triptycene, enables the formation of large-area molecular films with long-range 2D structural integrity up to the centimeter length scale by vacuum evaporation, spin-coating, and cooling from the isotropic liquid of the triptycene. X-ray diffraction analysis and microscopic observations reveal that triptycene molecules form a completely oriented 2D (hexagonal triptycene array) + 1D (layer stacking) structure, which is key for the long-range propagation of structural order. PMID:26045433

  1. Method of improving field emission characteristics of diamond thin films

    DOEpatents

    Krauss, A.R.; Gruen, D.M.

    1999-05-11

    A method of preparing diamond thin films with improved field emission properties is disclosed. The method includes preparing a diamond thin film on a substrate, such as Mo, W, Si and Ni. An atmosphere of hydrogen (molecular or atomic) can be provided above the already deposited film to form absorbed hydrogen to reduce the work function and enhance field emission properties of the diamond film. In addition, hydrogen can be absorbed on intergranular surfaces to enhance electrical conductivity of the diamond film. The treated diamond film can be part of a microtip array in a flat panel display. 3 figs.

  2. Method of improving field emission characteristics of diamond thin films

    DOEpatents

    Krauss, Alan R. (Naperville, IL); Gruen, Dieter M. (Downer Grove, IL)

    1999-01-01

    A method of preparing diamond thin films with improved field emission properties. The method includes preparing a diamond thin film on a substrate, such as Mo, W, Si and Ni. An atmosphere of hydrogen (molecular or atomic) can be provided above the already deposited film to form absorbed hydrogen to reduce the work function and enhance field emission properties of the diamond film. In addition, hydrogen can be absorbed on intergranular surfaces to enhance electrical conductivity of the diamond film. The treated diamond film can be part of a microtip array in a flat panel display.

  3. The role of microstructural phenomena in magnetic thin films

    SciTech Connect

    Laughlin, D.E.; Lambeth, D.N.

    1992-01-01

    The subject is germane to magnetic recording media. Results during the first 2 years are presented under the following headings: atomic resolution TEM of CoNiCr films; CoNiCr and CoCrTa thin films; development of texture; and CoSm/Cr thin films. The HREM results showed that defects in Co-based films may be responsible for higher coercivity. Findings are presented on the effects of Cr interlayers on the microstructure of the second Co-based film in Co/Cr/Co/Cr multilayer films. Proposed research plans are outlined.

  4. The role of microstructural phenomena in magnetic thin films

    SciTech Connect

    Laughlin, D.E.; Lambeth, D.N.

    1992-12-31

    The subject is germane to magnetic recording media. Results during the first 2 years are presented under the following headings: atomic resolution TEM of CoNiCr films; CoNiCr and CoCrTa thin films; development of texture; and CoSm/Cr thin films. The HREM results showed that defects in Co-based films may be responsible for higher coercivity. Findings are presented on the effects of Cr interlayers on the microstructure of the second Co-based film in Co/Cr/Co/Cr multilayer films. Proposed research plans are outlined.

  5. Silicon films with gallium-rich nanoinclusions: from superconductor to insulator

    NASA Astrophysics Data System (ADS)

    Heera, V.; Fiedler, J.; Hübner, R.; Schmidt, B.; Voelskow, M.; Skorupa, W.; Skrotzki, R.; Herrmannsdörfer, T.; Wosnitza, J.; Helm, M.

    2013-08-01

    Si films sputter deposited on thermally oxidized Si are enriched with Ga by ion implantation through a SiO2 capping layer. The morphology and the electrical transport properties of these films are investigated after rapid thermal annealing. Amorphous, Ga-rich nanoinclusions are embedded in a nanocrystalline Si matrix. The metallic nanoinclusions become superconducting below 7 K. They form a random network of junctions to heavily doped Si crystallites. Small modifications of the junction properties, e.g. by annealing or current pulses, can dramatically change the electronic transport in the film. Ga-rich Si films show a wealth of low-temperature transport phenomena, which have been known until now only from granular metals or high-temperature superconductors: superconductor-insulator transition, quasi-reentrant superconductivity and current-controlled sheet resistance. The possibility to prepare and modify Ga-rich Si films with microelectronics-compatible technology makes them interesting for both fundamental research on transport phenomena in nanostructured, disordered superconductors as well as for the integration of superconducting circuits into Si devices.

  6. Niobium Nitride Thin Films and Multilayers for Superconducting Radio Frequency Cavities

    NASA Astrophysics Data System (ADS)

    Roach, William; Beringer, Douglas; Li, Zhaozhu; Clavero, Cesar; Lukaszew, Rosa

    2013-03-01

    Niobium nitride in thin film form has been considered for a number of applications including multi-layered coatings onto superconducting radio frequency cavities which have been proposed to overcome the fundamental accelerating gradient limit of ~50 MV/m in niobium based accelerators. In order to fulfill the latter application, the selected superconductor's thermodynamic critical field, HC, must be larger than that of niobium and separated from the Nb surface by an insulating layer in order to shield the Nb cavity from field penetration and thus allow higher field gradients. Thus, for the successful implementation of such multilayered stack it is important to consider not just the materials inherent properties but also how these properties may be affected in thin film geometry and also by the specific deposition techniques used. Here, we show the results of our correlated study of structure and superconducting properties in niobium nitride thin films and discuss the shielding exhibited in NbN/MgO/Nb multilayer samples beyond the lower critical field of Nb for the first time. Niobium nitride in thin film form has been considered for a number of applications including multi-layered coatings onto superconducting radio frequency cavities which have been proposed to overcome the fundamental accelerating gradient limit of ~50 MV/m in niobium based accelerators. In order to fulfill the latter application, the selected superconductor's thermodynamic critical field, HC, must be larger than that of niobium and separated from the Nb surface by an insulating layer in order to shield the Nb cavity from field penetration and thus allow higher field gradients. Thus, for the successful implementation of such multilayered stack it is important to consider not just the materials inherent properties but also how these properties may be affected in thin film geometry and also by the specific deposition techniques used. Here, we show the results of our correlated study of structure and superconducting properties in niobium nitride thin films and discuss the shielding exhibited in NbN/MgO/Nb multilayer samples beyond the lower critical field of Nb for the first time. This work was funded by the Defense Threat Reduction Agency (HDTRA-10-1-0072).

  7. Electrodeposition and Characterization of Yttrium Barium Copper Oxide Superconducting Thin Films

    NASA Astrophysics Data System (ADS)

    Weston, Alan James

    Precursor thin films of Y-Ba-Cu-O superconductor were produced by potentiostatic and pulse electrodeposition from the dissolved nitrate salts of Y, Ba, Cu in dimethylformamide (DMF). The films were deposited on metal foils such as Ag-coated Cu, Ag, Ni, and Zr. Films were also synthesized on Ag-coated SrTiO_3, CaTiO _3, and Al_2O _3. The electrodeposited films were heat treated in flowing O_2 in order to produce the superconducting phase. The film composition as a function of the salt concentration in DMF was determined by energy dispersive x-ray analysis. Surface compositions were obtained by Auger electron spectroscopy. Crystal structure and phases were identified by means of x-ray diffraction. The superconducting dimagnetic behaviour has been observed in magnetic measurements. Films formed by pulse plating on the titanates and on Zr exhibited the best uniformity with highest T_{rm c}. Y-Ba-Cu-O films formed on Zr had highest T_{rm c} onset at 93 K (resistance measurement). The pulse plating process was extended to the synthesis of Er-Ba-Cu-O films. On Zr, the latter resulted in a T_{rm c} onset at 80 K.

  8. Pulsed laser deposition of thin superconducting films of Ho1Ba2Cu3O7 _x and Y1Ba2Cu3O7 _ x

    E-print Network

    Geohegan, David B.

    and yttrium for energy densities below 0.6 and 0.4 J cm"2, respectively. The films were stoichiometric successfully to deposit thin films of the high-7]. oxide superconductors YiBa2Cu3O7_^17"22 and La185Sr015CuO4 10%. At low laser energy densities, however, deficien- cies of yttrium have been reported in annealed

  9. Structural and Optical Properties of Nanoscale Galinobisuitite Thin Films

    PubMed Central

    Abd-Elkader, Omar H.; Deraz, N. M.

    2014-01-01

    Galinobisuitite thin films of (Bi2S3)(PbS) were prepared using the chemical bath deposition technique (CBD). Thin films were prepared by a modified chemical deposition process by allowing the triethanolamine (TEA) complex of Bi3+ and Pb2+ to react with S2? ions, which are released slowly by the dissociation of the thiourea (TU) solution. The films are polycrystalline and the average crystallite size is 35 nm. The composition of the films was measured using the atomic absorption spectroscopy (AAS) technique. The films are very adherent to the substrates. The crystal structure of Galinobisuitite thin films was calculated by using the X-ray diffraction (XRD) technique. The surface morphology and roughness of the films were studied using scanning electron microscopes (SEM), transmission electron microscopes (TEM) and stylus profilers respectively. The optical band gaps of the films were estimated from optical measurements. PMID:24473136

  10. A survey of thin-film solar photovoltaic industry & technologies

    E-print Network

    Grama, Sorin

    2007-01-01

    A new type of solar cell technology using so-called thin-film solar photovoltaic material has the potential to make a great impact on our lives. Because it uses very little or no silicon at all, thin- film (TF) solar ...

  11. Thermal Sensor Arrays for The Combinatorial Analysis of Thin Films

    E-print Network

    Thermal Sensor Arrays for The Combinatorial Analysis of Thin Films A dissertation presented Advisor Author Joost J. Vlassak Patrick J. McCluskey Thermal Sensor Arrays for The Combinatorial Analysis of Thin Films Abstract Membrane-based thermal sensor arrays were developed for the high- throughput

  12. Enhanced polarization conversion for an anisotropic thin film

    Microsoft Academic Search

    Yi-Jun Jen; Cheng-Lung Chiang

    2006-01-01

    This work presents an explicit expression for the reflection and transmission coefficients of an anisotropic thin film in the general case in which the optical axis and the incident ray are arbitrarily directed in three dimensions. The polarization conversion quantities for reflected light from an anisotropic thin film are calculated and analyzed for two three-layered systems. With light incident from

  13. Microstructure and properties of copper thin films on silicon substrates

    E-print Network

    Jain, Vibhor Vinodkumar

    2009-05-15

    copper thin films but on an expense of conductivity. This study proposes a technique to deposit high strength and high conductivity copper thin films on different silicon substrates at room temperature. Single crystal Cu (100) and Cu (111) have been grown...

  14. Synthesis and Characterization of Functional Nanostructured Zinc Oxide Thin Films

    E-print Network

    Chow, Lee

    -temperature thin film growth technique has been developed to fabricate a new generation of smart and functional nanostructured metal oxide thin film materials. This chemical synthetic route uses stable and inexpensive metal to 100 ppm ammonia at temperatures between 20 °C and 300 °C have been assessed. Introduction

  15. Optimal grid-based methods for thin film micromagnetics simulations

    E-print Network

    Muratov, Cyrill

    ­3]. Of particular interest are these structures in thin magnetic metal films [4­8] which have been intensely play an important role in multilayer magnetic-normal metal struc- tures for current-induced reversalOptimal grid-based methods for thin film micromagnetics simulations C.B. Muratov a,*, V.V. Osipov b

  16. Two-dimensional microscanner actuated by PZT thin film

    Microsoft Academic Search

    Wen-Mei Lin; Andreas Schroth; Sohei Matsumoto; Chengkuo Lee; Ryutaro Maeda

    1999-01-01

    This paper introduces the fabrication and characterization of 2D resonant microscanners actuated by sol-gel deposited PZT thin films. The piezoelectric PZT thin films with silicon micromachining technology provide the advantages of high scanning frequencies and low driving voltages. The actuation principle is based on the bimorph beam structure, which consists of an oxide layer and a piezoelectric PZT layer. The

  17. Applications of thin-film thermocouples for surface temperature measurement

    NASA Astrophysics Data System (ADS)

    Martin, Lisa C.; Holanda, Raymond

    1994-10-01

    Thin film thermocouples provide a minimally intrusive means of measuring surface temperature in hostile, high temperature environments. Unlike wire thermocouples, thin films do not necessitate any machining of the surface, thereby leaving intact its structural integrity. Thin films are many orders of magnitude thinner than wire, resulting in less disruption to the gas flow and thermal patterns that exist in the operating environment. Thin film thermocouples have been developed for surface temperature measurement on a variety of engine materials. The sensors are fabricated in the NASA Lewis Research Center's Thin Film Sensor Lab, which is a Class 1000 Clean Room. The thermocouples are platinum-13% rhodium vs platinum and are fabricated by the sputtering process. Thin film-to-leadwire connections are made using the parallel-gap welding process. Thermocouples have been developed for use on superalloys, ceramics and ceramic composites, and intermetallics. Some applications of thin film thermocouples are: temperature measurement of Space Shuttle Main Engine turbine blade materials, temperature measurement in gas turbine engine testing of advanced materials, and temperature and heat flux measurements in a diesel engine. Fabrication of thin film thermocouples is described. Sensor durability, drift rate, and maximum temperature capabilities are addressed.

  18. Nanoengineered Thin Films for Solid Oxide Fuel Cells 

    E-print Network

    Su, Qing

    2013-11-21

    and lattice strain. Fifth, Two-phase (Ce0.9Gd0.1O1.95)0.5/(Zr0.92Y0.08O1.96)0.5 nanocomposite thin films with vertically aligned structure are grown as the electrolyte for thin film solid oxide fuel cells (TFSOFCs). More than 50% increase in overall power...

  19. Electrochromic switching of monolithic Prussian blue thin film devices.

    PubMed

    Liu, Jianxi; Zhou, Wencai; Walheim, Stefan; Wang, Zhengbang; Lindemann, Peter; Heissler, Stefan; Liu, Jinxuan; Weidler, Peter G; Schimmel, Thomas; Wöll, Christof; Redel, Engelbert

    2015-06-01

    Monolithic, crystalline and highly oriented coordination network compound (CNC) Prussian blue (PB) thin films have been deposited though different routes on conductive substrates. Characterization of the monolithic thin films reveals a long-term stability, even after many redox cycles the crystallinity as well as the high orientation remain intact during the electrochromic switching process. PMID:26072745

  20. Active optoelectronics using thin-film organic semiconductors

    Microsoft Academic Search

    Stephen R. Forrest

    2000-01-01

    We review recent results in the emerging area of organic semiconductor materials. Light-emitting devices, thin-film transistors and ultrafast photodetectors are used as examples to show the progress made in our understanding of the fundamental optoelectronic properties of organic thin films, and their application to active electronic devices. Also, a perspective of the potential of these materials for practical application following

  1. Ferroelectric thin films: Review of materials, properties, and applications

    Microsoft Academic Search

    N. Setter; D. Damjanovic; L. Eng; G. Fox; S. Gevorgian; S. Hong; A. Kingon; H. Kohlstedt; N. Y. Park; G. B. Stephenson; I. Stolitchnov; A. K. Taganstev; D. V. Taylor; T. Yamada; S. Streiffer

    2006-01-01

    An overview of the state of art in ferroelectric thin films is presented. First, we review applications: microsystems' applications, applications in high frequency electronics, and memories based on ferroelectric materials. The second section deals with materials, structure (domains, in particular), and size effects. Properties of thin films that are important for applications are then addressed: polarization reversal and properties related

  2. Multifunctional oxide thin films for magnetoelectric and electromechanical applications

    Microsoft Academic Search

    Seung Hyub Baek

    2010-01-01

    Epitaxial multifunctional oxide thin films have been extensively researched to understand and exploit a variety of their physical properties. In order to integrate such versatile properties into real devices, there are several critical issues: (1) high-quality thin film growth, (2) fundamental understanding on reliable performance, and (3) device fabrication process preserving functionality of oxides. We have investigated all these issues,

  3. UV imprinting for thin film solar cell application

    Microsoft Academic Search

    J Escarré; C Battaglia; K Söderström; C Pahud; R Biron; O Cubero; F-J Haug; C Ballif

    2012-01-01

    UV imprinting is an interesting, low cost technique to produce large area thin film solar cells incorporating nanometric textures. Here, we review and present new results confirming that replicas of the most common textures used in photovoltaics can be obtained by UV imprinting with an excellent fidelity. The use of these replicas as substrates for amorphous and micromorph thin film

  4. Femtosecond pulsed laser deposition of silicon thin films

    PubMed Central

    2013-01-01

    Optimisation of femtosecond pulsed laser deposition parameters for the fabrication of silicon thin films is discussed. Substrate temperature, gas pressure and gas type are used to better understand the deposition process and optimise it for the fabrication of high-quality thin films designed for optical and optoelectronic applications. PMID:23758871

  5. Tools to Synthesize the Learning of Thin Films

    ERIC Educational Resources Information Center

    Rojas, Roberto; Fuster, Gonzalo; Slusarenko, Viktor

    2011-01-01

    After a review of textbooks written for undergraduate courses in physics, we have found that discussions on thin films are mostly incomplete. They consider the reflected and not the transmitted light for two instead of the four types of thin films. In this work, we complement the discussion in elementary textbooks, by analysing the phase…

  6. Peeling from a biomimetically patterned thin elastic film

    Microsoft Academic Search

    L. Mahadevan; Manoj K. Chaudhury; Vijay Shenoy

    2004-01-01

    Inspired by the observation that many naturally occurring adhesives arise as tex- tured thin films, we consider the displacement-controlled peeling of a flexible plate from an incision-patterned thin adhesive elastic layer. We find that crack initiation from an incision on the film occurs at a load much higher than that required to propagate it on a smooth adhesive surface; multiple

  7. Simulations of microdomain lattice defects in block copolymer thin films

    Microsoft Academic Search

    August W. Bosse

    2006-01-01

    In this dissertation we discuss three studies of microdomain ordering in block copolymer thin films. In the first study we report on two new numerical techniques for removing metastable microdomain defects that can be used in field-theoretic computer simulations of block copolymer thin films: (1) a spectral amplitude filter (SF) which encourages the simulation to relax into high symmetry states

  8. Parallel molecular dynamics simulation on thin-film formation process

    Microsoft Academic Search

    Huawei Chen; Ichiro Hagiwara; Dawei Zhang; Tian Huang

    2005-01-01

    Chemical vapor deposition is regarded as one of the most promising methods of epitaxial growth for materials such as thin films, nanotubes, etc. The properties of such thin films depend on the states of cluster such as initial velocity, size, etc. We developed parallel molecule dynamics using the potential of the embedded atom method (EAM), which can make the scale

  9. Thermal conductivity measurements of thin-film resist Dachen Chua)

    E-print Network

    Pease, R. Fabian W.

    Thermal conductivity measurements of thin-film resist Dachen Chua) Solid State and Photonics out-of-plane and in-plane thermal conductivity of thin resist films following different exposure conditions. An optical thermoreflectance technique was used to characterize out-of-plane thermal conductivity

  10. STABILITY OF COMPRESSIVE AND UNDERCOMPRESSIVE THIN FILM TRAVELLING WAVES

    E-print Network

    stability of compressive and undercompressive traveling waves in thin film models. AssociatedSTABILITY OF COMPRESSIVE AND UNDERCOMPRESSIVE THIN FILM TRAVELLING WAVES Andrea Bertozzi 1 Center Shearer 2 Center for Research in Scientific Computation and Department of Mathematics North Carolina State

  11. Modular, Thin Film Solar Arrays for Operationally Responsive Spacecraft

    Microsoft Academic Search

    W. Zuckermandel; S. Enger; N. Gupta; J. Summers

    2007-01-01

    MicroSat Systems, Inc. (MSI) has developed a low cost, lightweight, solar array system using thin-film photovoltaic (TFPV) material to meet power generation needs for future responsive space missions. The Folded Integrated Thin Film Stiffener (FITS) is the deployment portion of the system. FITS is an integrated, passively deployed solar array structure designed specifically for TFPV, however a variety of photovoltaic

  12. Advanced electrochromic devices based on WO 3 thin films

    Microsoft Academic Search

    S Papaefthimiou; G Leftheriotis; P Yianoulis

    2001-01-01

    We present work on the development of advanced materials suitable for use as electrochromic thin films (EC), ion storage layers and transparent conductors (TC) in electrochromic devices. These thin film layers were prepared in our laboratory by thermal evaporation and electron gun deposition. They were incorporated into electrochromic devices, which were subsequently characterized by optical and electrochemical techniques such as

  13. THIN FILM MECHANICS BULGING AND Ph.D Dissertation

    E-print Network

    Huston, Dryver R.

    are perhaps the most important of these applications. The semiconductor industry is responsible-like structures that are fabricated from a thin film that has had the substrate removed from a small region the mechanical properties, in particular the elastic modulus and residual stress of a thin film window. Air

  14. CHARACTERIZATION OF URANIUM, URANIUM OXIDE AND SILICON MULTILAYER THIN FILMS

    E-print Network

    Hart, Gus

    CHARACTERIZATION OF URANIUM, URANIUM OXIDE AND SILICON MULTILAYER THIN FILMS by David T. Oliphant. Woolley Dean, College of Physical and Mathematical Sciences #12;ABSTRACT CHARACTERIZATION OF URANIUM, URANIUM OXIDE AND SILICON MULTILAYER THIN FILMS David T. Oliphant Department of Physics and Astronomy

  15. STRESS-INDUCED PERIODIC FRACTURE PATTERNS IN THIN FILMS Alex A. Volinsky1

    E-print Network

    Volinsky, Alex A.

    STRESS-INDUCED PERIODIC FRACTURE PATTERNS IN THIN FILMS Alex A. Volinsky1 , Neville R. Moody2 applied stresses in thin films can cause film fracture. In the case of compressive stress thin film stress a network of through- thickness cracks forms in thin films. Excessive biaxial residual stress

  16. Dynamic interfaces in an organic thin film

    PubMed Central

    Tao, Chenggang; Liu, Qiang; Riddick, Blake C.; Cullen, William G.; Reutt-Robey, Janice; Weeks, John D.; Williams, Ellen D.

    2008-01-01

    Low-dimensional boundaries between phases and domains in organic thin films are important in charge transport and recombination. Here, fluctuations of interfacial boundaries in an organic thin film, acridine-9-carboxylic acid on Ag(111), have been visualized in real time and measured quantitatively using scanning tunneling microscopy. The boundaries fluctuate via molecular exchange with exchange time constants of 10–30 ms at room temperature, with length-mode fluctuations that should yield characteristic f?1/2 signatures for frequencies less than ?100 Hz. Although acridine-9-carboxylic acid has highly anisotropic intermolecular interactions, it forms islands that are compact in shape with crystallographically distinct boundaries that have essentially identical thermodynamic and kinetic properties. The physical basis of the modified symmetry is shown to arise from significantly different substrate interactions induced by alternating orientations of successive molecules in the condensed phase. Incorporating this additional set of interactions in a lattice–gas model leads to effective multicomponent behavior, as in the Blume–Emery–Griffiths model, and can straightforwardly reproduce the experimentally observed isotropic behavior. The general multicomponent description allows the domain shapes and boundary fluctuations to be tuned from isotropic to highly anisotropic in terms of the balance between intermolecular interactions and molecule–substrate interactions. PMID:18765797

  17. Apparatus for laser assisted thin film deposition

    DOEpatents

    Warner, Bruce E. (Pleasanton, CA); McLean, II, William (Oakland, CA)

    1996-01-01

    A pulsed laser deposition apparatus uses fiber optics to deliver visible output beams. One or more optical fibers are coupled to one or more laser sources, and delivers visible output beams to a single chamber, to multiple targets in the chamber or to multiple chambers. The laser can run uninterrupted if one of the deposition chambers ceases to operate because other chambers can continue their laser deposition processes. The laser source can be positioned at a remote location relative to the deposition chamber. The use of fiber optics permits multi-plexing. A pulsed visible laser beam is directed at a generally non-perpendicular angle upon the target in the chamber, generating a plume of ions and energetic neutral species. A portion of the plume is deposited on a substrate as a thin film. A pulsed visible output beam with a high pulse repetition frequency is used. The high pulse repetition frequency is greater than 500 Hz, and more preferably, greater than about 1000 Hz. Diamond-like-carbon (DLC) is one of the thin films produced using the apparatus.

  18. Advancements in PMR thin-film media

    NASA Astrophysics Data System (ADS)

    Judy, J. H.

    2005-02-01

    The purpose of this paper is to review advancements in the design, characterization, and optimization of PMR thin film media for magnetic recording output, resolution, signal-to-noise, and thermal stability at ultra-high densities from 100 to 1000 Gbpsi. In particular, the single and double-layer PMR thin-film media to be discussed include HCP CoCr-alloys, HCP CGC CoPt/CoCrPt, FCC Co/Pd multilayers, HCP CoCrPt-SiO 2 granular oxides, FCT FePt, and tilted media. This paper reviews the materials processing techniques used to optimize physical microstructures with seed layers and intermediate layers to decrease grain size, narrow size distribution, dope with elements to inhibit grain growth, segregate elements to grain boundaries to enhance magnetic isolation, and increase coercivity, magnetization squareness, negative nucleation field, narrow easy-axis orientation, switching field distribution, and reduce hysteresis loop slope at coercivity, magnetic cluster domain size, DC reversed domain noise, and recording transition jitter noise.

  19. Photoinduced drift of electrons in thin magnetic films

    Microsoft Academic Search

    N. N. Krupa

    2001-01-01

    The results are presented of experimental studies of variations in the polarization of light reflected from multilayer thin\\u000a metal films containing nonmagnetic Bi or Ti films and a TbFe magnetic film magnetized in the direction perpendicular to the\\u000a film plane. An additional optical rotation of light reflected from bismuth and titanium films was observed upon their irradiation\\u000a by intense nanosecond

  20. Pulsed DC reactive magnetron sputtering of aluminum nitride thin films

    Microsoft Academic Search

    Jung Won Cho

    2002-01-01

    Aluminum nitride thin films have been deposited by pulsed DC reactive magnetron sputtering. The pulsed DC power provides arc-free deposition of insulating films. Two types of pulsed DC (unipolar and asymmetric bipolar) were studied with respect to characteristics and properties of resultant films. The crystal structure of the AlN films was examined by XRD. The microstructures of the AlN films

  1. Interfacial structure of photoresist thin films in developer solutions

    NASA Astrophysics Data System (ADS)

    Prabhu, Vivek M.; Vogt, Bryan D.; Wu, Wen-Li; Douglas, Jack F.; Lin, Eric K.; Satija, Sushil K.; Goldfarb, Dario L.; Ito, Hiroshi

    2005-05-01

    A depth profile of the base developer counterion concentration within thin photoresist films was measured in-situ using contrast variant specular neutron reflectivity to characterize the initial swelling stage of the film dissolution. We find a substantial counterion depletion near the substrate and an enrichment near the periphery of the film extending into the solution. These observations challenge our understanding of the charge distribution in photoresist and polyelectrolyte films and are important for understanding film dissolution in medical and technological applications.

  2. Development of a thin film solid state gaseous HCl sensor

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The selection of materials to develop a thin film HCl sensor is discussed. Data were primarily concerned with chemical and physical properties of the film and with electrical properties which exhibit and enhance electrical response when HCl is absorbed on the film surface. Techniques investigated for enhancing electrical response include changing conditions for growing films, adding impurities to the film, changing ambient light intensity, and altering the ambient temperature of the sensing element.

  3. Tensile and Adhesion Properties of Metal Thin Films Deposited onto Polyester Film Substrate Prepared by a Conventional Vacuum Evaporator

    NASA Astrophysics Data System (ADS)

    Kita, Takuya; Saitoh, Shou; Iwamori, Satoru

    Four kinds of metal, such as aluminum, copper, indium and tin, thin films were deposited onto polyester (PET) substrate by a conventional vacuum evaporator and evaluated their tensile and adhesion properties. The tensile property was estimated by observations of micro-cracks of the thin films due to the tensile test at 150°C. The tensile property of the metal thin films seems to relate with Brinell hardness and thickness of the thin film. The adhesion property of these metal thin films was estimated by measuring the pull strength. Aluminum thin film showed highest pull strength of all the thin films, and the pull strength increased with increase of the thickness.

  4. Studies on superconducting thin films for SRF applications

    SciTech Connect

    Tajima, Tsuyoshi [Los Alamos National Laboratory; Haberkorn, Nestor [Los Alamos National Laboratory; Civale, Leonardo [Los Alamos National Laboratory; Hawley, Marilyn [Los Alamos National Laboratory; Schulze, Roland [Los Alamos National Laboratory; Zocco, Adam [Los Alamos National Laboratory; Eremeev, Grigory [TJNAF; Guo, Jiquan [SLAC; Dolgashev, Valery [SLAC; Martin, David [SLAC; Tantawi, Sami [SLAC; Yoneda, Charles [SLAC; Doi, Toshiya [KAGOSHIMA UNIV.; Matsumoto, Akiyoshi [NIMS

    2010-09-09

    In order to overcome the fundamental limit of Nb's critical magnetic field ({approx} 200 mT) that corresponds to E{sub acc} {approx}50 MV/m, an idea of coating several thin layers of a superconductor has been proposed. MgB{sub 2}, a superconductor that has a T{sub c} of {approx}39 K, has been studied to explore the effect of coating in terms of DC and RF critical magnetic fields, and RF surface losses. MgB{sub 2} has shown an excellent behavior, although there is some discrepancy between DC and RF measurements.

  5. A Model for Tear Film Thinning With Osmolarity and Fluorescein

    PubMed Central

    Braun, Richard J.; Gewecke, Nicholas R.; Begley, Carolyn G.; King-Smith, P. Ewen; Siddique, Javed I.

    2014-01-01

    Purpose. We developed a mathematical model predicting dynamic changes in fluorescent intensity during tear film thinning in either dilute or quenching regimes and we model concomitant changes in tear film osmolarity. Methods. We solved a mathematical model for the thickness, osmolarity, fluorescein concentration, and fluorescent intensity as a function of time, assuming a flat and spatially uniform tear film. Results. The tear film thins to a steady-state value that depends on the relative importance of the rates of evaporation and osmotic supply, and the resulting increase of osmolarity and fluorescein concentrations are calculated. Depending on the initial thickness, the rate of osmotic supply and the tear film thinning rate, the osmolarity increase may be modest or it may increase by as much as a factor of eight or more from isosmotic levels. Regarding fluorescent intensity, the quenching regime occurs for initial concentrations at or above the critical fluorescein concentration where efficiency dominates, while lower concentrations show little change in fluorescence with tear film thinning. Conclusions. Our model underscores the importance of using fluorescein concentrations at or near the critical concentration clinically so that quenching reflects tear film thinning and breakup. In addition, the model predicts that, depending on tear film and osmotic factors, the osmolarity within the corneal compartment of the tear film may increase markedly during tear film thinning, well above levels that cause marked discomfort. PMID:24458153

  6. Development of Thin-Film Battery Powered Transdermal Medical Devices

    SciTech Connect

    Bates, J.B.; Sein, T.

    1999-07-06

    Research carried out at ORNL has led to the development of solid state thin-film rechargeable lithium and lithium-ion batteries. These unique devices can be fabricated in a variety of shapes and to any required size, large or small, on virtually any type of substrate. Because they have high energies per unit of volume and mass and because they are rechargeable, thin-film lithium batteries have potentially many applications as small power supplies in consumer and special electronic products. Initially, the objective of this project was to develop thin-film battery powered products. Initially, the objective of this project was to develop thin-film battery powered transdermal electrodes for recording electrocardiograms and electroencephalograms. These ''active'' electrode would eliminate the effect of interference and improve the reliability in diagnosing heart or brain malfunctions. Work in the second phase of this project was directed at the development of thin-film battery powered implantable defibrillators.

  7. Tailoring Thin Film-Lacquer Coatings for Space Application

    NASA Technical Reports Server (NTRS)

    Peters, Wanda C.; Harris, George; Miller, Grace; Petro, John

    1998-01-01

    Thin film coatings have the capability of obtaining a wide range of thermal radiative properties, but the development of thin film coatings can sometimes be difficult and costly when trying to achieve highly specular surfaces. Given any space mission's thermal control requirements, there is often a need for a variation of solar absorptance (Alpha(s)), emittance (epsilon) and/or highly specular surfaces. The utilization of thin film coatings is one process of choice for meeting challenging thermal control requirements because of its ability to provide a wide variety of Alpha(s)/epsilon ratios. Thin film coatings' radiative properties can be tailored to meet specific thermal control requirements through the use of different metals and the variation of dielectric layer thickness. Surface coatings can be spectrally selective to enhance radiative coupling and decoupling. The application of lacquer to a surface can also provide suitable specularity for thin film application without the cost and difficulty associated with polishing.

  8. Physical properties in thin films of iron oxides.

    SciTech Connect

    Uribe, J. D.; Osorio, J.; Barrero, C. A.; Girata, D.; Morales, A. L.; Hoffmann, A.; Materials Science Division; Univ. de Antioquia

    2008-01-01

    We have grown hematite ({alpha}-Fe{sub 2}O{sub 3}) thin films on stainless steel substrates and magnetite (Fe{sub 3}O{sub 4}) thin films on (0 0 1)-Si single crystal substrates by a RF magnetron sputtering process. {alpha}-Fe{sub 2}O{sub 3} thin films were grown in an Ar atmosphere at substrate temperatures around 400 C, and Fe{sub 3}O{sub 4} thin films in an Ar/O{sub 2} reactive atmosphere at substrate temperatures around 500 C. Conversion electron Moessbauer (CEM) spectra of {alpha}-Fe{sub 2}O{sub 3} thin films exhibit values for hyperfine parameter characteristic of the hematite stoichiometric phase in the weak ferromagnetic state [R.E. Vandenberghe, in: Moessbauer Spectroscopy and Applications in Geology, University Gent, Belgium, 1990. [1

  9. Nonlinear optical microscopy for imaging thin films and surfaces

    SciTech Connect

    Smilowitz, L.B.; McBranch, D.W.; Robinson, J.M.

    1995-03-01

    We have used the inherent surface sensitivity of second harmonic generation to develop an instrument for nonlinear optical microscopy of surfaces and interfaces. We have demonstrated the use of several nonlinear optical responses for imaging thin films. The second harmonic response of a thin film of C{sub 60} has been used to image patterned films. Two photon absorption light induced fluorescence has been used to image patterned thin films of Rhodamine 6G. Applications of nonlinear optical microscopy include the imaging of charge injection and photoinduced charge transfer between layers in semiconductor heterojunction devices as well as across membranes in biological systems.

  10. Preparation of Electrically Conductive Au Thin Films by Colloid Sedimentation.

    PubMed

    Petek, Urša; Bukovec, Peter; Kozjek Škofic, Irena

    2015-01-01

    A novel and facile wet-chemical method for the preparation of Au thin films is presented. These Au thin films were deposited on glass substrates by the gravitational sedimentation of Au colloids. The colloids were formed by chemical reduction in ethanol using HAuCl4 and NaBH4 with no added surfactants. Without stabilizing agents the colloids quickly aggregated, settled to the bottom and formed a thin film. The sedimentation of the colloids was monitored using UV-vis spectroscopy. Thin films with Au loads ranging between 0.25 and 4.0 g m-2 were prepared and characterized by means of UV-vis spectroscopy, electrical resistance measurements, optical microscopy, scanning electron microscopy, and cyclic voltammetry. The results showed that nanostructured Au films with a very high specific surface area were formed. The films were electrically conductive and partially transparent to visible light. PMID:26085408

  11. An overview of thin film nitinol endovascular devices.

    PubMed

    Shayan, Mahdis; Chun, Youngjae

    2015-07-15

    Thin film nitinol has unique mechanical properties (e.g., superelasticity), excellent biocompatibility, and ultra-smooth surface, as well as shape memory behavior. All these features along with its low-profile physical dimension (i.e., a few micrometers thick) make this material an ideal candidate in developing low-profile medical devices (e.g., endovascular devices). Thin film nitinol-based devices can be collapsed and inserted in remarkably smaller diameter catheters for a wide range of catheter-based procedures; therefore, it can be easily delivered through highly tortuous or narrow vascular system. A high-quality thin film nitinol can be fabricated by vacuum sputter deposition technique. Micromachining techniques were used to create micro patterns on the thin film nitinol to provide fenestrations for nutrition and oxygen transport and to increase the device's flexibility for the devices used as thin film nitinol covered stent. In addition, a new surface treatment method has been developed for improving the hemocompatibility of thin film nitinol when it is used as a graft material in endovascular devices. Both in vitro and in vivo test data demonstrated a superior hemocompatibility of the thin film nitinol when compared with commercially available endovascular graft materials such as ePTFE or Dacron polyester. Promising features like these have motivated the development of thin film nitinol as a novel biomaterial for creating endovascular devices such as stent grafts, neurovascular flow diverters, and heart valves. This review focuses on thin film nitinol fabrication processes, mechanical and biological properties of the material, as well as current and potential thin film nitinol medical applications. PMID:25839120

  12. Vertically aligned biaxially textured molybdenum thin films

    SciTech Connect

    Krishnan, Rahul [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Riley, Michael [Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Lee, Sabrina [US Army Armament Research, Development and Engineering Center, Benet Labs, Watervliet, New York 12189 (United States); Lu, Toh-Ming [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2011-09-15

    Vertically aligned, biaxially textured molybdenum nanorods were deposited using dc magnetron sputtering with glancing flux incidence (alpha = 85 degrees with respect to the substrate normal) and a two-step substrate-rotation mode. These nanorods were identified with a body-centered cubic crystal structure. The formation of a vertically aligned biaxial texture with a [110] out-of-plane orientation was combined with a [-110] in-plane orientation. The kinetics of the growth process was found to be highly sensitive to an optimum rest time of 35 seconds for the two-step substrate rotation mode. At all other rest times, the nanorods possessed two separate biaxial textures each tilted toward one flux direction. While the in-plane texture for the vertical nanorods maintains maximum flux capture area, inclined Mo nanorods deposited at alpha = 85 degrees without substrate rotation display a [-1-1-4] in-plane texture that does not comply with the maximum flux capture area argument. Finally, an in situ capping film was deposited with normal flux incidence over the biaxially textured vertical nanorods resulting in a thin film over the porous nanorods. This capping film possessed the same biaxial texture as the nanorods and could serve as an effective substrate for the epitaxial growth of other functional materials.

  13. Comparison of CleaningComparison of Cleaning Methods for Thin Film SurfacesMethods for Thin Film Surfaces

    E-print Network

    Hart, Gus

    Measurement methodsmethods 2.2. Cleaning methodsCleaning methods --OpticleanOpticlean®® --Plasma EtchPlasma Etch --UV lampEllipsometry Cleaning methods testedCleaning methods tested ­­ OpticleanOpticlean ­­ UV LampUV Lamp ­­ Plasma EtchPlasmaComparison of CleaningComparison of Cleaning Methods for Thin Film SurfacesMethods for Thin Film

  14. 23.5% thin-film space concentrator cells

    Microsoft Academic Search

    B. D. Dingle; R. P. Gale; R. W. McClelland; M. B. Spitzer; H. B. Curtis; D. J. Brinker

    1990-01-01

    Thin-film AlGaAs-GaAs double-heterostructure concentrator cells were fabricated which exhibit total-area conversion efficiencies as high as 23.5% AM0 at 100 suns, 25°C. This is one of the best space concentrators measured to date at NASA and is designed for a thin-film cell without a prismatic coverglass. This solar cell structure consists of a GaAs\\/AlGaAs film less than 5 ?m thick mounted

  15. Thin film coatings for space electrical power system applications

    SciTech Connect

    Gulino, D.A.

    1988-09-01

    This paper examines some of the ways in which thin film coatings can play a role in aerospace applications. Space systems discussed include photovoltaic and solar dynamic electric power generation systems, including applications in environmental protection, thermal energy storage, and radiator emittance enhancement. Potential applications of diamondlike films to both atmospheric and space based systems are examined. Also, potential uses of thin films of the recently discovered high-temperature superconductive materials are discussed.

  16. Electrical conductivity of nanocrystalline ceria and zirconia thin films

    Microsoft Academic Search

    Igor Kosacki; Toshio Suzuki; Vladimir Petrovsky; Harlan U Anderson

    2000-01-01

    The results of studies of the preparation, structure and electrical conductivity of ZrO2:16% Y and CeO2 thin films are presented. Dense films with grain size controlled in the region of 1–400 nm have been obtained on monocrystalline sapphire and polycrystalline Al2O3 substrates using a polymeric precursor spin coating method. The electrical conductivity of nanocrystalline thin films has been studied as

  17. Photolithography I: Thin Film Deposition and Mask Design

    NSDL National Science Digital Library

    Buhrman, Robert A.

    In this lab, students design, fabricate and test four Al resistors using some of the techniques that are employed to make integrated circuits. First, students will evaporate a thin film of aluminum on a Si wafer. Then, they will use photolithographic techniques to pattern the film and etch away unwanted parts, leaving only your resistors. Students will complete the Al thin film deposition and mask design parts of the process. For the second part of this laboratory activity, click here.

  18. Characterization of Nickel Oxide Thin Film --- DC Reactive Magnetron Sputtering

    Microsoft Academic Search

    K. Ashok

    2011-01-01

    Nickel oxide (NiO) thin films were deposited on glass substrates by reactive direct current (DC) magnetron sputtering of a Ni target in an Ar\\/O2 mixture. The effect of thickness (0.2 mum, 0.4 mum and 1 mum) on the structural and surface morphological properties of NiO thin films was investigated. These films were characterized by X-ray diffraction (XRD), Fourier transform infrared

  19. Deposition of aluminium oxide thin films by reactive magnetron sputtering

    Microsoft Academic Search

    K Koski; J Hölsä; P Juliet

    1999-01-01

    Aluminium oxide thin films were deposited by direct current (d.c.) reactive magnetron sputtering on glass-slide, silicon wafer, stainless-steel and polycarbonate substrates. The thicknesses of the films were between 200nm and 3.0?m. The deposition was controlled by the target voltage to obtain stoichiometric thin films with a high deposition rate. The deposition process was studied in terms of target power, I–U

  20. Thermal analysis of laser damage in thin-film photoconductors

    Microsoft Academic Search

    M. Kruer; L. Esterowitz; F. Bartoli; R. Allen

    1976-01-01

    A closed-form thermal model is presented which describes heat transfer in thin-film photoconductors under laser irradiation. Previously published thermal models for laser damage are not valid for thin-film detectors fabricated with thick protective layers. In these detectors it is necessary to take into account heat diffusion from the absorbing film into the protective layer as well as the substrate. The

  1. Properties of crystalline gamma-TeO2 thin film

    Microsoft Academic Search

    Namrata Dewan; K. Sreenivas; Vinay Gupta

    2007-01-01

    Thin films of tellurium dioxide (TeO2) were prepared by RF diode sputtering at room temperature (RT). The effects of post-deposition annealing in temperature range RT to 400 °C on the structural and optical properties of the deposited thin films were studied. The films were characterized using X-ray diffraction, infrared (IR) absorption spectroscopy, Raman spectroscopy and ultraviolet visible (UV vis) transmittance

  2. Characterization of vacuum-evaporated ZnSe thin films

    Microsoft Academic Search

    S. Venkatachalam; Y. L. Jeyachandran; P. Sureshkumar; A. Dhayalraj; D. Mangalaraj; Sa. K. Narayandass; S. Velumani

    2007-01-01

    ZnSe thin films were prepared at different thicknesses using a vacuum evaporation technique under a vacuum of 3.9×10?8 bar. The composition, structure, optical and electrical properties of the deposited ZnSe thin films were studied using the energy dispersive X-ray analysis (EDAX), X-ray diffraction (XRD), optical transmittance and current–voltage measurements. The composition of the deposited films was found to be Zn

  3. Interconnected Si nanocrystals forming thin films with controlled bandgap values

    SciTech Connect

    Nychyporuk, T.; Zakharko, Yu.; Lysenko, V.; Lemiti, M. [Lyon Institut of Nanotechnologies (INL), CNRS UMR-5270, University of Lyon, INSA de Lyon, 7 avenue Jean Capelle, Bat. Blaise Pascal, 69621 Villeurbanne Cedex (France)

    2009-08-24

    Interconnected Si nanocrystals forming homogeneous thin films with controlled bandgap values from 1.2 to 2.9 eV were formed by pulsed plasma enhanced chemical vapor deposition technique under dusty plasma conditions. The chosen values of plasma duration time correspond to specific phases of the dust nanoparticle growth. Structural and optical properties of the deposited nanostructured films are described in details. These nanocrystalline Si thin films seem to be promising candidates for all-Si tandem solar cell applications.

  4. Planar tunneling into YBCMO (M = zinc, nickel) thin films

    Microsoft Academic Search

    Elvira Badica

    2001-01-01

    Planar tunneling spectroscopy of Zn and Ni-doped Y1Ba 2Cu3O7-delta thin films is reported. The tunneling conductance is studied as a function of crystallographic orientation, doping concentration, temperature and applied magnetic field. Tunnel junctions are fabricated with either Bi or Pb as a counter-electrode, ex-situ, on thin films grown by off-axis DC magnetron sputter deposition from single stoichiometric targets. Films are

  5. Uniaxial anisotropy in magnetite thin film—Magnetization studies

    Microsoft Academic Search

    A. Wiechec; J. Korecki; B. Handke; Z. Kakol; D. Owoc; D. A. Antolak; A. Kozlowski

    2006-01-01

    Magnetization and electrical resistivity measurements have been performed on a stoichiometric single crystalline magnetite Fe3O4 thin film (thickness of ca. 500nm) MBE deposited on MgO (100) substrate. The aim of these studies was to check the influence of preparation method and sample form (bulk vs. thin film) on magnetic anisotropy properties in magnetite. The film magnetization along ?001? versus applied

  6. Thin film adhesion by nanoindentation-induced superlayers. Final report

    SciTech Connect

    Gerberich, William W.; Volinsky, A.A.

    2001-06-01

    This work has analyzed the key variables of indentation tip radius, contact radius, delamination radius, residual stress and superlayer/film/interlayer properties on nanoindentation measurements of adhesion. The goal to connect practical works of adhesion for very thin films to true works of adhesion has been achieved. A review of this work titled ''Interfacial toughness measurements of thin metal films,'' which has been submitted to Acta Materialia, is included.

  7. Properties of Thin Films of High-Permeability Alloys

    Microsoft Academic Search

    B. L. Flur; A. J. Griest

    1966-01-01

    A number of commercially available high-permeability nickel-iron-base alloys with low values of coercive force, magnetostriction, and crystalline anisotropy are of potential interest as materials for thin-film memory elements. Because of their compositional complexity, however, films of these alloys are not easily prepared by vacuum deposition. By use of bias sputtering, thin films of Mumetal, Conetic AA, Supermalloy, and 4–79 Permalloy

  8. Spectral and optical recording properties of azo nickel thin film

    Microsoft Academic Search

    Yongyou Geng; Donghong Gu; Fuxi Gan

    2004-01-01

    A new azo nickel chelate (Ni(azo)2) thin film has been developed for digital versatile disc recordable (DVD-R) by means of a spin-coating method. The absorption and reflectivity of the film matches very well with the wavelength of the GaAlInP semiconductor diode laser (650nm). Optical parameters of the thin film were measured by a spectroscopic ellipsometer system. Thermal property of azo

  9. Fracture of nanoporous organosilicate thin films

    NASA Astrophysics Data System (ADS)

    Gage, David Maxwell

    Nanoporous organosilicate thin films are attractive candidates for a number of emerging technologies, ranging from biotechnology to optics and microelectronics. However, integration of these materials is challenged by their fragile nature and susceptibility to mechanical failure. Debonding and cohesive cracking of the organosilicate film are principal concerns that threaten the reliability and yield of device structures. Despite the intense interest in these materials, there is currently a need for greater understanding of the relationship between glass structure and thermomechanical integrity. The objective of this research was to investigate strategies for improving mechanical performance through variations in film chemistry, process conditions, and pore morphology. Several approaches to effecting improvements in elastic and fracture properties were examined in depth, including post-deposition curing, molecular reinforcement using hydrocarbon network groups, and manipulation of pore size and architecture. Detailed structural characterization was employed along with quantitative fracture mechanics based testing methods. It was shown that ultra-violet irradiation and electron bombardment post-deposition treatments can significantly impact glass structure in ways that cannot be achieved through thermal activation alone. Both techniques demonstrated high porogen removal efficiency and enhanced the glass matrix through increased network connectivity and local bond rearrangements. The increases in network connectivity were achieved predominantly through the replacement of terminal groups, particularly methyl and silanol groups, with Si-O network bonds. Nuclear magnetic resonance spectroscopy was shown to be a powerful and quantitative method for gaining new insight into the underlying cure reactions and mechanisms. It was demonstrated that curing leads to significant progressive enhancement of elastic modulus and adhesive fracture energies due to increased network bond density that results from higher network connectivity along with slight densification of the film. At the same time, the curing produced only a modest progressive increase in dielectric constant, indicating that ultra-violet and electron beam curing show great promise for the processing of low-k and ultra low-k organosilicate films. However, some general limitations of the curing processes were also discovered. In particular, the cohesive fracture energies of organosilicate films were found to be largely insensitive to curing. This was shown to be due to a crack meandering phenomenon in which the crack undergoes small-scale deflections toward local regions of free volume and reduced network bond density, thereby mitigating the effects of curing. Additionally, neither ultra-violet nor electron-beam curing were successful at improving adhesion at the lower film to barrier interface, suggesting little or no curing effects at the bottom portion of the dielectric layer. Sol-gel condensation of carbon-bridged organosilanes was used to prepare low-k films that feature hydrocarbon network bonds in lieu of terminal organic substituents. The hydrocarbon ligaments served to preserve connectivity and reinforce the glass network, resulting in remarkable improvements in elastic modulus and fracture resistance relative to competing carbon-doped oxides or SSQ derived materials of the same dielectric constant. The improvements in fracture resistance were rationalized in terms of a bridging contribution during stretching and rupture of the hydrocarbon chains that was found to scale with the length of the bridging hydrocarbon group. Additionally, the Si-C bonds in the bridged organosilicates made these films less prone to moisture assisted cracking than their silica-based and SSQ counterparts. The bridged organosilicate films demonstrated outstanding mechanical properties even at high porosity, making them excellent candidates for ultra low-k porous applications. The impact of pore morphology on the fracture of nanoporous films was also examined. For a given pore generating sche

  10. Polycrystalline silicon conductivity modulated thin film transistors

    NASA Astrophysics Data System (ADS)

    Anish, Kumar K. P.

    1997-09-01

    Polycrystalline silicon (poly-Si) thin-film transistors (TFTs) on glass has received significant attention for use in large area microelectronic applications. These applications include both niche and large volume applications such as printer drivers, image scanners, active-matrix liquid crystal displays (AMLCDs), electro-luminescent displays, plasma assisted displays, etc. Currently, the leading technology for these applications is amorphous-Si (a-Si) TFT. However, as the information content increases, a-Si technology encounters severe challenges due to its inherent low mobility, high parasitic capacitance, low aperture ratio, and non-compatibility to CMOS process. On the other hand, poly-Si technology offers high mobility, low parasitic capacitance, small size, CMOS compatibility, good stability, and uses the infrastructure of silicon science and technology. Thus, a simple low temperature poly-Si technology which allows large area system integration on panel will be in great demand for future high definition displays. However, it was found that poly-Si material properties vary with its method of preparation, its grain size, its surface roughness, and the nature and distribution of the inter-granular and bulk defects. Therefore, extensive studies are needed to optimize the key parameters such as the off-current, on-current, and breakdown voltage of the devices. These parameters can be optimized by means of material preparation as well as innovative device designs. In this thesis, three TFT structures were invented and fabricated using a simple low temperature poly-Si technology. With these novel structures, pixels, pixel drivers, and analog and digital peripheral circuits can all be built on the same glass substrate. This allows the ultimate goal of display systems on glass to be much more closer to reality. First, a high voltage transistor called the Conductivity Modulated Thin Film Transistor (CMTFT) is presented. Using this structure, the fundamental current pinching problem of the conventional high voltage offset drain TFT is completely eliminated. Experimental results show that the CMTFT can handle three orders of magnitude higher current than that of the conventional offset drain TFT while still providing low leakage current, high breakdown voltage, and fast switching speed. It is very suitable to be used as pixel drivers and high voltage printer drivers. In order to implement efficient pixel transistors and design analog peripheral circuits on glass, a second novel structure called the double-gate Elevated-Channel Thin Film Transistor (ECTFT) is invented. The ECTFT exhibits kink-free IV characteristics and low leakage current compared to the conventional uniform thin- and thick-film devices. Furthermore, the double-gate operation of the device provides much higher output current, high on/off current ratio, and steeper subthreshold slope compared to the uniform film devices. All of these result in efficient pixels and high performance analog devices to be built on glass. Finally, to further optimize the CMTFT using the ECTFT technology, a third novel structure called the double-gate Elevated Channel CMTFT (EC-CMTFT) is fabricated. Combining the advantages of elevated channel and conductivity modulation, the EC-CMTFT has a four times reduction in offset region resistance and a five times larger on/off current ratio compared to the CMTFTs.

  11. Integrated thin film cadmium sulfide solar cell module

    NASA Technical Reports Server (NTRS)

    Mickelsen, R. A.; Abbott, D. D.

    1971-01-01

    The design, development, fabrication and tests of flexible integrated thin-film cadmium sulfide solar cells and modules are discussed. The development of low cost and high production rate methods for interconnecting cells into large solar arrays is described. Chromium thin films were applied extensively in the deposited cell structures as a means to: (1) achieve high adherence between the cadmium sulfide films and the vacuum-metallized copper substrates, (2) obtain an ohmic contact to the cadmium sulfide films, and (3) improve the adherence of gold films as grids or contact areas.

  12. High-Temperature Superconducting/Ferroelectric, Tunable Thin-Film Microwave Components

    NASA Technical Reports Server (NTRS)

    Miranda, Felix A.

    1998-01-01

    At the NASA Lewis Research Center, ferroelectric films such as SrTiO3 and Ba(sub x)Sr(sub 1-x)TiO3, are being used in conjunction with YBa(sub 2)Cu(sub 3)O(sub 7-delta) high-temperature superconducting thin films to fabricate tunable microwave components such as filters, phase shifters, and local oscillators. These structures capitalize on the variation of the dielectric constant of the ferroelectric film upon the application of a direct-current electric field, as well as on the low microwave losses of high-temperature superconductors relative to their conventional conductor counterparts. For example, the surface resistance for a YBa(sub 2)Cu(sub 3)O(sub 7-delta) thin film at 10 GHz and 77 K is more than two orders of magnitude lower than that of copper or gold at the same temperature and frequency. SrTiO3 and Ba(sub x)Sr(sub 1-x)TiO3 films are used because their crystal structure and lattice parameters are similar to those of YBa(sub 2)Cu(sub 3)O(sub 7-delta), thus enabling the growth of highly textured YBa(sub 2)Cu(sub 3)O(sub 7-delta) films with high critical current densities (i.e., greater than 1 MA/sq cm) on the underlying ferroelectric film, or alternatively, of highly textured ferroelectric film on the underlying YBa(sub 2)Cu(sub 3)O(sub 7-delta) film.

  13. Nonlinear optical and acoustic properties of thin films

    Microsoft Academic Search

    N. V. Tcherniega; M. I. Samoilovich; A. D. Kudryavtseva; A. F. Belyanin; P. V. Pashchenko; N. N. Dzbanovskiy

    2011-01-01

    The nonlinear optical and acoustic properties of thin films have been studied experimentally. The following nonlinear effects\\u000a have been investigated: acoustic wave generation; stimulated light scattering due to acousto-optic interaction; and the influence\\u000a of excitation conditions, film structure, and film composition on the above effects.

  14. Ion-assisted deposition of lanthanum fluoride thin films

    Microsoft Academic Search

    James D. Targove; John P. Lehan; Linda J. Lingg; H. Angus Macleod; J. A. Leavitt; McIntyre L. C. Jr

    1987-01-01

    Ion-assisted deposition has been used to deposit lanthanum fluoride thin films with near-unity film packing densities and no significant increase in absorption. Rutherford backscattering analysis has determined the effect of ion bombardment on the film stoichiometries including the degree of fluorine deficiency. Oxygen atoms or compounds appear to occupy most of the available anion vacancies if sufficient oxygen is available

  15. Investigation of the thermal properties of thin films of aluminum

    Microsoft Academic Search

    Iu. A. Volkov; L. S. Palatnik; A. T. Pugachev

    1976-01-01

    Experiments were conducted to determine the thermal conductivity and diffusivity of thin films (100-1000 A) of aluminum, Joule heated inside an electron diffraction chamber. The temperature fields were calculated from electron diffraction patterns of the heated film, and thermal conductivity and diffusivity were obtained from the one dimensional heat equation for a film with current. Thermal conductivity is studied as

  16. Effective Biaxial Anisotropy in Double-Layered Thin Magnetic Films

    Microsoft Academic Search

    Nobuo Hayashi; Elichi Goto

    1966-01-01

    Quantitative experimental results have been obtained in support of a previously developed theory which represents the deformation of the critical curves of multilayered magnetic thin films in terms of effective multiaxial anisotropies. The effective biaxial anisotropy field has been experimentally observed to be proportional to the square of film thickness in the case of thinner films, as expected from the

  17. Characterization of thin films by optical mixing spectroscopy

    Microsoft Academic Search

    E. E. Uzgiris

    1973-01-01

    Adsorption of thin films of polymer or protein onto polystyrene spheres in aqueous solutions is studied by optical mixing spectroscopy. The film is characterized as to hydrodynamic thickness, optical thickness, and surface charge density. These quentities are used to infer some aspects of the film structure.

  18. In situ monitoring of thin film deposition using optical fibers

    Microsoft Academic Search

    Pfeifer

    1991-01-01

    A novel technique to monitor thin film deposition has been developed using optical fibers. The system measures the optical thickness of a film and not the physical thickness which results in accurate film deposition for optical applications regardless of deposition conditions. A discussion of the mathematics necessary to understand the operation of the system is presented. The details of the

  19. Investigations on solution derived aluminium doped zinc oxide thin films

    Microsoft Academic Search

    S. B Majumder; M Jain; P. S Dobal; R. S Katiyar

    2003-01-01

    Aluminium (Al) doped transparent zinc oxide thin films have been successfully grown on sapphire (0001) substrates by an economical chemical solution deposition technique. These films were characterized in terms of their structural, optical, and electrical properties. Detailed XPS analysis of the O1s core level spectra has been carried out for the ZnO films annealed at different temperatures. Lower binding energy

  20. Method for forming thin films having superconductive contacts

    Microsoft Academic Search

    R. E. Joynson; C. A. Neugebauer; J. R. Rairden

    1970-01-01

    Superconductive contacts are formed on a thin film of niobium, tantalum and their alloys by the selective deposition of a superconductive contact metal atop the film within the chamber employed for the film deposition without breaching the vacuum of the chamber between depositions. Preferably metals forming a soft oxide layer, e.g. tin, are employed to form the contacts and the

  1. Vapor growth of electrochromic thin films of transition metal oxides

    Microsoft Academic Search

    K. A. Gesheva; T. Ivanova; B. Marsen; G. Zollo; M. Kalitzova

    2008-01-01

    Mixed oxide films of transition metals gain considerable much attention due to their interesting optoelectronic properties. The low temperature chemical vapor growth processing of thin films of mixed W and Mo oxides is presented. The investigation is related to optimization of films structure and the related optoelectronic properties in dependence on the chemical vapor deposition (CVD) process parameters. Their electrochromic

  2. Improved process for making thin-film sodium niobate capacitors

    NASA Technical Reports Server (NTRS)

    Micka, E. Z.

    1968-01-01

    Sodium niobate, formed by high vacuum, flash, and reactive evaporations, has a high dielectric constant and is used as a thin film dielectric in microelectronic capacitors. High purity films are formed from relatively inexpensive, pure starting materials. Crystalline sodium niobate films can be formed on amorphous or crystalline materials.

  3. Thin liquid film technique — application to water–oil–water bitumen emulsion films

    Microsoft Academic Search

    Khr Khristov; S. D Taylor; J Czarnecki; J Masliyah

    2000-01-01

    We describe an adaptation of the thin liquid film-pressure balance technique (TLF-PBT) for a systematic study of water\\/diluted-bitumen\\/water thin films. Recent research into the stability of water-in-oil emulsions, particularly those occurring in the oil industry, has not properly addressed the dependence of the emulsion stability on the thin films that are formed between approaching water droplets. The objective of this

  4. Highly c-axis oriented CaRuO3 thin films on LaAlO3 buffered Si(100) substrates by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Tian, H. Y.; Wang, J.; Wang, Y.; Qi, J. Q.; Wong, K. H.; Chan, H. L. W.; Choy, C. I.

    2004-11-01

    Highly c-axis oriented CaRuO3 thin films were prepared on LaAlO3 buffered Si(100) substrates at 650 °C by pulsed laser deposition. The buffer layer had a significant effect on the microstructure and electrical properties of the subsequent CaRuO3 thin films. Typical columnar grown CaRuO3 films were available using LaAlO3 as a buffer layer, although the buffer layer was not well-crystallized at the deposition temperature. The resistivity of the highly oriented CaRuO3 thin film was 287.8 ?.cm at room temperature. The film showed typical metallic behaviour and its resistivity was sufficiently low to be used as a buffer layer in superconductor tapes or electrode materials in dielectrics devices.

  5. Optoelectronic Characterization of Hyperdoped Silicon Thin Films

    NASA Astrophysics Data System (ADS)

    Hutchinson, David

    Pulsed laser melting has been shown to be capable of producing crystalline Silicon (Si) films which contain dopant concentrations as high as one atom % (of order 1x1020 atoms/cm2). These materials have demonstrated very high absorption coefficients both above and below the Si bandgap. In some cases these devices have also demonstrated strong internal gain. This thesis explores a series of characterization techniques to provide insight into the optoelectronic properties of devices which employ these highly doped thin films. These techniques provide a methodology which can be expanded into future analysis of novel semiconductor films which may contain large concentration gradients or demonstrate internal gain. Through a combination of optoelectronic techniques insight into device transport behavior can guide the design of future devices incorporating hyperdoped films. By controlling the surface illumination conditions the locations within devices where photocarriers are generated can be manipulated. This level of control allows for the investigation of carrier transport behavior within the films. Two primary techniques are employed to control illumination conditions. The first is Light Beam Induced Current surface mapping. This technique provided experimental confirmation of sub-band photocurrent response within gold hyperdoped silicon. This technique also allowed for the electronic characterization of the internal gain demonstrated by single crystal sulfur hyperdoped material. The electronic properties of this gain are most effectively described with a trapped carrier barrier height lowering mechanism. The second technique investigates the spectral dependence of photoresponse. Hyperdoped materials contain large concentration gradients which can also have absorption coefficients which vary strongly with wavelength. Varying the wavelength of illumination will significantly impact the distribution of generated carriers within the sample, which will significantly impact carrier extraction probabilities. Modeling of this technique is able to describe the relative spectral response of sulfur hyperdoped diodes with a range of layer thicknesses. By assuming low extraction rates from carriers generated within hyperdoped regions, spectral response can be fit to a simple absorption model. The spectral dependence of photoresponse also provides a lower limit of 10-8 cm2/V on the effective mobility-lifetime product for the extraction of holes generated within the hyperdoped layer of a film deposited on silicon on insulator substrate. The cross-section for recombination at these concentrations appears to be much lower than in the case of isolated sulfur impurities.

  6. Characterization of Thin Films and Coatings

    SciTech Connect

    Baer, Donald R.; Thevuthasan, Suntharampillai

    2010-01-01

    Just as the numbers and types of thin films have grown dramatically, the needs and approaches for their characterization have also expanded significantly. Adequate characterization of a film or coating depends on the process to create the coating as well as the planned or potential application(s) and expected lifetime. Characterization of a coating or film necessarily requires application of methods that determine properties of the coating and not primarily the substrate. This places some focus on methods that determine properties of layers and not "bulk" material. However, the increasing importance of micro- and nano-structures in coatings and films places an increased importance in methods with high spatial resolution. The growing use of organic films and coatings and the importance of molecular functionalization of inorganic surfaces increase the importance for different types of molecular characterization tools. In most circumstances appropriate characterization requires use of a combination of tools. The purpose of this chapter is to provide an introduction to the basic methods and overview applications for some of the most important tools for characterization of films, coatings and surfaces. The chapter will be organized in six sections: • Technique Overview – This section provides a high level summary of the types of information that can be obtained by different methods and includes information about their sensitivity and resolution. • Incident Photon Methods – Techniques involving incident photons are described and some brief examples of application are shown. Methods included are: x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), x-ray reflectivity (XRR), Fourier transform infra-red spectroscopy (FTIR), laser Raman spectroscopy, ellipsometry, and photoluminescence spectroscopy. • Incident Ion Methods - Methods initiated by ion irradiation are summarized including: Rutherford backscattering spectrometry (RBS), nuclear reaction analysis (NRA), ion channeling, elastic recoil detection analysis (ERDA), secondary ion mass spectrometry (SIMS), glow discharge mass spectrometry and uses of focused ion beams (FIB) (often in combination with scanning electron microscopy). • Incident Electron Methods – Methods involving incident electrons include: Auger electron spectroscopy (AES), scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDS), transmission electron microscopy (TEM), and electron diffraction (low energy electron diffraction [LEED] and reflection high energy electron diffraction [RHEED]). • Other Methods – Additional methods described include scanning probe microscopy (SPM) (including scanning tunneling microscopy [STM] and atomic force microscopy [AFM]) and atom probe microscopy.

  7. Patterns and conformations in molecularly thin films

    NASA Astrophysics Data System (ADS)

    Basnet, Prem B.

    Molecularly thin films have been a subject of great interest for the last several years because of their large variety of industrial applications ranging from micro-electronics to bio-medicine. Additionally, molecularly thin films can be used as good models for biomembrane and other systems where surfaces are critical. Many different kinds of molecules can make stable films. My research has considered three such molecules: a polymerizable phospholipid, a bent-core molecules, and a polymer. One common theme of these three molecules is chirality. The phospolipid molecules studied here are strongly chiral, which can be due to intrinsically chiral centers on the molecules and also due to chiral conformations. We find that these molecules give rise to chiral patterns. Bent-core molecules are not intrinsically chiral, but individual molecules and groups of molecules can show chiral structures, which can be changed by surface interactions. One major, unconfirmed hypothesis for the polymer conformation at surface is that it forms helices, which would be chiral. Most experiments were carried out at the air/water interface, in what are called Langmuir films. Our major tools for studying these films are Brewster Angle Microscopy (BAM) coupled with the thermodynamic information that can be deduced from surface pressure isotherms. Phospholipids are one of the important constituents of liposomes -- a spherical vesicle com-posed of a bilayer membrane, typically composed of a phospholipid and cholesterol bilayer. The application of liposomes in drug delivery is well-known. Crumpling of vesicles of polymerizable phospholipids has been observed. With BAM, on Langmuir films of such phospholipids, we see novel spiral/target patterns during compression. We have found that both the patterns and the critical pressure at which they formed depend on temperature (below the transition to a i¬‘uid layer). Bent-core liquid crystals, sometimes knows as banana liquid crystals, have drawn increasing attention because of the richness in phases that they exhibit. Due to the unique coupling between dipole properties and the packing constraints placed by the bent shape, these molecules are emerging as strong candidates in electromechanical devices. However, most applications require that the molecules be aligned, which has proved difficult. Our group has tested such molecules both as Langmuir layers and, when transferred to a solid, as alignment layers with some limited success. However, these molecules do not behave well with the surfaces and the domains at the air/water interface tend to form ill-controlled multilayer structures since attraction with the surfaces is relatively weak. New bent-core molecules obtained from Prof. Dr. C. Tsehiemke from Department of Chemistry Institute of Organic Chemistry, Martin-Luther-University, Germany, have a hydrophilic group at one end. We expect this molecule to behave better on the surface because of the stronger attraction of the hydrophilic group towards the surface than for the bent-core molecules without the hydrophilic group. Polydimethylsiloxane (PDMS) is a polymer which finds many applications in modifying surface properties. It is used in manufacturing lubricants, protective coatings, hair conditioner and glass-coating. However its properties are not well understood. This polymer has been proposed to follow either helical or caterpillar conformations on a surface. The orientational order of CH3 side groups can test for these conformations (they would be predominantly up/down for the caterpillar conformation, but rotating through the entire 360 degree for the helical one). Thus previous work on the Langmuir polymer films at the air/water interface were complemented by deuterium NMR studies to probe their conformations at a surface. These experiments were performed using humid porous solids, in order to provide sufficient surface area for the technique. Previous tests in this group at room temperature were suggestive but inconclusive because of the rapid averaging motion of the molecules. Here, we attempt t

  8. Transparent Conductive Oxides in Thin Film Photovoltaics

    NASA Astrophysics Data System (ADS)

    Hamelmann, Frank U.

    2014-11-01

    This paper show results from the development of transparent conductive oxides (TCO's) on large areas for the use as front electrode in thin film silicon solar modules. It is focused on two types of zinc oxide, which are cheap to produce and scalable to a substrate size up to 6 m2. Low pressure CVD with temperatures below 200°C can be used for the deposition of boron doped ZnO with a native surface texture for good light scattering, while sputtered aluminum doped ZnO needs a post deposition treatment in an acid bath for a rough surface. The paper presents optical and electrical characterization of large area samples, and also results about long term stability of the ZnO samples with respect to the so called TCO corrosion.

  9. Characterization of lithium phosphorous oxynitride thin films

    SciTech Connect

    Yu, Xiaohua; Bates, J.B.; Jellison, G.E. Jr.

    1996-01-01

    Electrical and electrochemical properties of an amorphous thin-film lithium electrolyte, lithium phosphorous oxynitride (Lipon), have been studied with emphasis on the stability window vs Li metal and the behavior of the Li/Lipon interface. Ion conductivity of Lipon exhibits Arrhenius behavior at {minus}26 to +140 C, with a conductivity of 1.7 {times} 10{sup {minus}6}S/cm at 25 C and an activity energy of 0.50 {plus_minus} 0.01 eV. A stability window of 5.5 V was observed with respect to a Li{sup +}/Li reference, and no detectable reaction or degradation was evident at the Li/Lipon interface upon lithium cycling.

  10. Glow discharge plasma deposition of thin films

    DOEpatents

    Weakliem, Herbert A. (Pennington, NJ); Vossen, Jr., John L. (Bridgewater, NJ)

    1984-05-29

    A glow discharge plasma reactor for deposition of thin films from a reactive RF glow discharge is provided with a screen positioned between the walls of the chamber and the cathode to confine the glow discharge region to within the region defined by the screen and the cathode. A substrate for receiving deposition material from a reactive gas is positioned outside the screened region. The screen is electrically connected to the system ground to thereby serve as the anode of the system. The energy of the reactive gas species is reduced as they diffuse through the screen to the substrate. Reactive gas is conducted directly into the glow discharge region through a centrally positioned distribution head to reduce contamination effects otherwise caused by secondary reaction products and impurities deposited on the reactor walls.

  11. Modeling of polycrystalline thin film solar cells

    NASA Astrophysics Data System (ADS)

    Fahrenbruch, Alan L.

    1999-03-01

    This paper describes modeling polycrystalline thin-film solar cells using the program AMPS-1D1 to visualize the relationships between the many variables involved. These simulations are steps toward two dimensional modeling the effects of grain boundaries in polycrystalline cells. Although this paper describes results for the CdS/CdTe cell, the ideas presented here are applicable to copper-indium-gallium selenide (CIGS) cells as well as other types of cells. Results of these one-dimensional simulations are presented: (a) the duplication of experimentally observed cell parameters, (b) the effects of back-contact potential barrier height and its relation to stressing the cell, (c) the effects of the depletion layer width in the CdTe layer on cell parameters, and (d) the effects of CdS layer thickness on the cell parameters. Experience using the software is also described.

  12. Nanocrystalline silicon thin films for thermoelectric applications

    NASA Astrophysics Data System (ADS)

    Queen, Daniel; Jugdersuren, Battogtokh; Culberston, Jim; Wang, Qi; Nemeth, William; Metcalf, Tom; Liu, Xiao

    2014-03-01

    Recent advances in thermoelectric materials have come from reductions in thermal conductivity by manipulating both chemical composition and nanostructure to limit the phonon mean free path. However, wide spread applications for some of these materials may be limited due to high raw material and integration costs. In this talk we will discuss our recent results on nanocrystalline silicon thin films deposited by both hot-wire and plasma enhanced chemical vapor deposition where the nanocrystal size and crystalline volume fraction are varied by dilution of the silane precursor gas with hydrogen. Nanocyrstalline silicon is an established material technology used in multijunction amorphous silicon solar cells and has the potential to be a low cost and scalable material for use in thermoelectric devices. This work supported by the Office of Naval Research and the National Research Council.

  13. Electrochromism: from oxide thin films to devices

    NASA Astrophysics Data System (ADS)

    Rougier, A.; Danine, A.; Faure, C.; Buffière, S.

    2014-03-01

    In respect of their adaptability and performance, electrochromic devices, ECDs, which are able to change their optical properties under an applied voltage, have received significant attention. Target applications are multifold both in the visible region (automotive sunroofs, smart windows, ophthalmic lenses, and domestic appliances (oven, fridge…)) and in the infrared region (Satellites Thermal Control, IR furtivity). In our group, focusing on oxide thin films grown preferentially at room temperature, optimization of ECDs performances have been achieved by tuning the microstructure, the stoichiometry and the cationic composition of the various layers. Herein, our approach for optimized ECDs is illustrated through the example of WO3 electrochromic layer in the visible and in the IR domain as well as ZnO based transparent conducting oxide layer. Targeting the field of printed electronics, simplification of the device architecture for low power ECDs is also reported.

  14. Structure of Thin-Film Lithium Microbatteries

    NASA Technical Reports Server (NTRS)

    Whitacre, Jay F. (Inventor); Bugga, Ratnakumar V. (Inventor); West, William C. (Inventor)

    2003-01-01

    A process for making thin-film batteries including the steps of cleaning a glass or silicon substrate having an amorphous oxide layer several microns thick; defining with a mask the layer shape when depositing cobalt as an adhesion layer and platinum as a current collector; using the same mask as the preceding step to sputter a layer of LiC(0)O2, on the structure while rocking it back and forth; heating the substrate to 300 C. for 30 minutes; sputtering with a new mask that defines the necessary electrolyte area; evaporating lithium metal anodes using an appropriate shadow mask; and, packaging the cell in a dry-room environment by applying a continuous bead of epoxy around the active cell areas and resting a glass slide over the top thereof. The batteries produced by the above process are disclosed.

  15. Photonic Diagnostic Technique For Thin Photoactive Films

    NASA Technical Reports Server (NTRS)

    Thakoor, Sarita

    1996-01-01

    Photonic diagnostic technique developed for use in noninvasive, rapid evaluation of thin paraelectric/ferroelectric films. Method proves useful in basic research, on-line monitoring for quality control at any stage of fabrication, and development of novel optoelectronic systems. Used to predict imprint-prone memory cells, and to study time evolution of defects in ferroelectric memories during processing. Plays vital role in enabling high-density ferroelectric memory manufacturing. One potential application lies in use of photoresponse for nondestructive readout of polarization memory states in high-density, high-speed memory devices. In another application, extension of basic concept of method makes possible to develop specially tailored ferrocapacitor to act as programmable detector, wherein remanent polarization used to modulate photoresponse. Large arrays of such detectors useful in optoelectronic processing, computing, and communication.

  16. Sputtering deposition of aluminium molybdenum alloy thin film anodes for thin film microbatteries

    NASA Astrophysics Data System (ADS)

    Thirumoolam, Mani Chandran; Sivaramakrishnan, Balaji; Devarajan, Mutharasu

    2015-05-01

    Al5Mo thin film anodes for Li-ion batteries were prepared using DC sputtering under different conditions, the latter being specified as deposition at room temperature (S0), deposition at 300°C (S1), and deposition at room temperature followed by thermal annealing at 300°C (S2). The thin films were deposited using an aluminum target tiled with molybdenum discs at a ratio calculated based on the theoretical sputtering yields. The structural and compositional analyses performed with x-ray diffraction (XRD) and energy-dispersive x-ray spectroscopy (EDX) confirmed the Al5Mo compound formation and the Al/Mo elemental ratio, respectively. The compound formation was observed to be evident only for the thin films subjected to heat treatment during or after deposition. Scanning electron micrographs reveal a higher porosity of approximately 23% for sample S0 and a lower porosity of around 18% for sample S1. The chronopotentiometry results show a higher volumetric specific capacity of approximately 197 mAh/cm3 for sample S1. Capacity increments have been observed for all samples upon charge-discharge cycles, whose values after 25 cycles for samples S0, S1, and S2 were 41.2%, 20.4%, and 21.1%, respectively. [Figure not available: see fulltext.

  17. Magnetic Characteristics of Copper Ion-Modified DNA Thin Films

    PubMed Central

    Dugasani, Sreekantha Reddy; Lee, Namhoon; Lee, Junwye; Kim, Byeonghoon; Hwang, Si Un; Lee, Keun Woo; Kang, Won Nam; Park, Sung Ha

    2013-01-01

    We developed a new method of fabricating a divalent copper ion (Cu2+) modified DNA thin film on a glass substrate and studied its magnetic properties. We evaluated the coercive field (Hc), remanent magnetization (Mr), susceptibility (?), and thermal variation of magnetization with varying Cu2+ concentrations [Cu2+] resulting in DNA thin films. Although thickness of the two dimensional DNA thin film with Cu2+ in dry state was extremely thin (0.6?nm), significant ferromagnetic signals were observed at room temperature. The DNA thin films with a [Cu2+] near 5?mM showed the distinct S-shape hysteresis with appreciable high Hc, Mr and ? at low field (?600?Oe). These were primarily caused by the presence of small magnetic dipoles of Cu2+ coordination on the DNA molecule, through unpaired d electrons interacting with their nearest neighbors and the inter-exchange energy in the magnetic dipoles making other neighboring dipoles oriented in the same direction. PMID:23660965

  18. Performance of hard DLC protective film prepared by PECVD method for thin film magnetic disk

    Microsoft Academic Search

    Keigo Iechika; Yuichi Kokaku; Mitsuyoshi Ootake; Katsuo Abe; Hiroshi Tani; Hiroshi Inaba

    1994-01-01

    Performance of a diamondlike carbon (DLC) film prepared by the PECVD method has been investigated as the protective film of a rigid thin film disk. An in-line sputtering PECVD multilayer deposition system was used for preparation of disk samples. The disks were found to be superior to those disks with conventionally sputtered carbon films in many aspects such as high

  19. thin films grown with additional NaF layers

    NASA Astrophysics Data System (ADS)

    Kim, Gee Yeong; Kim, Juran; Jo, William; Son, Dae-Ho; Kim, Dae-Hwan; Kang, Jin-Kyu

    2014-10-01

    CZTS precursors [SLG/Mo (300 nm)/ZnS (460 nm)/SnS (480 nm)/Cu (240 nm)] were deposited by RF/DC sputtering, and then NaF layers (0, 15, and 30 nm) were grown by electron beam evaporation. The precursors were annealed in a furnace with Se metals at 590°C for 20 minutes. The final composition of the CZTSSe thin-films was of Cu/(Zn + Sn) ~ 0.88 and Zn/Sn ~ 1.05, with a metal S/Se ratio estimated at ~0.05. The CZTSSe thin-films have different NaF layer thicknesses in the range from 0 to 30 nm, achieving a ~3% conversion efficiency, and the CZTSSe thin-films contain ~3% of Na. Kelvin probe force microscopy was used to identify the local potential difference that varied according to the thickness of the NaF layer on the CZTSSe thin-films. The potential values at the grain boundaries were observed to increase as the NaF thickness increased. Moreover, the ratio of the positively charged GBs in the CZTSSe thin-films with an NaF layer was higher than that of pure CZTSSe thin-films. A positively charged potential was observed around the grain boundaries of the CZTSSe thin-films, which is a beneficial characteristic that can improve the performance of a device.

  20. Thin-film Sensors for Space Propulsion Technology

    NASA Technical Reports Server (NTRS)

    Kim, W. S.; Englund, D. R.

    1985-01-01

    SSME components such as the turbine blades of the high pressure fuel turbopump are subjected to rapid and extreme thermal transients that contribute to blade cracking and subsequent failure. The objective was to develop thin film sensors for SSME components. The technology established for aircraft gas turbine engines was adopted to the materials and environment encountered in the SSME. Specific goals are to expand the existing thin film sensor technology, to continue developing improved sensor processing techniques, and to test the durability of aircraft gas turbine engine technology in the SSME environment. A thin film sensor laboratory is being installed in a refurbished clean room, and new sputtering and photoresist exposure equipment is being acquired. Existing thin film thermocouple technology in an SSME environment are being tested. Various coatings and their insulating films are being investigated for use in sensor development.

  1. Thin-film sensors for space propulsion technology

    NASA Astrophysics Data System (ADS)

    Kim, W. S.; Englund, D. R.

    1985-05-01

    SSME components such as the turbine blades of the high pressure fuel turbopump are subjected to rapid and extreme thermal transients that contribute to blade cracking and subsequent failure. The objective was to develop thin film sensors for SSME components. The technology established for aircraft gas turbine engines was adopted to the materials and environment encountered in the SSME. Specific goals are to expand the existing thin film sensor technology, to continue developing improved sensor processing techniques, and to test the durability of aircraft gas turbine engine technology in the SSME environment. A thin film sensor laboratory is being installed in a refurbished clean room, and new sputtering and photoresist exposure equipment is being acquired. Existing thin film thermocouple technology in an SSME environment are being tested. Various coatings and their insulating films are being investigated for use in sensor development.

  2. Atomic vapor deposition of bismuth titanate thin films

    NASA Astrophysics Data System (ADS)

    Deepak, Nitin; Zhang, Panfeng F.; Keeney, Lynette; Pemble, Martyn E.; Whatmore, Roger W.

    2013-05-01

    c-axis oriented ferroelectric bismuth titanate (Bi4Ti3O12) thin films were grown on (001) strontium titanate (SrTiO3) substrates by an atomic vapor deposition technique. The ferroelectric properties of the thin films are greatly affected by the presence of various kinds of defects. Detailed x-ray diffraction data and transmission electron microscopy analysis demonstrated the presence of out-of-phase boundaries (OPBs). It is found that the OPB density changes appreciably with the amount of titanium injected during growth of the thin films. Piezo-responses of the thin films were measured by piezo-force microscopy. It is found that the in-plane piezoresponse is stronger than the out-of-plane response, due to the strong c-axis orientation of the films.

  3. Quasiparticle Dynamics and Transport in Thin Ferromagnetic Nickel Films

    NASA Astrophysics Data System (ADS)

    Bron, W. E.; Guerra, A., III; Wu, W.

    1998-03-01

    It has recently been demonstrated that excitation of electronic carriers in thin metallic films by femtosecond duration laser pulses leads to non equilibrium particle dynamics and transport. The excited electronic carriers are generally referred to as quasiparticles and their dynamics have been shown to be governed by Fermi Liquid Theory. The quasiparticle transport occurs even in the absence of an external electric potential applied to the thin film. Instead, the transport is driven by a local concentration gradient of quasiparticles between the excited and non excited volumes of the film. We report here on the dynamics and transport of quasiparticles across itinerant ferromagnetic thin Nickel films of various thicknesses. We also report on the dynamics and transport of quasiparticles across thin Aluminum films of different thicknesses. We employed a front-back pump-probe excitation-detection technique to determine the dynamics and transport of the excited electronic carriers.

  4. Electrochemical Deposition of Lanthanum Telluride Thin Films and Nanowires

    NASA Astrophysics Data System (ADS)

    Chi, Su (Ike); Farias, Stephen; Cammarata, Robert

    2013-03-01

    Tellurium alloys are characterized by their high performance thermoelectric properties and recent research has shown nanostructured tellurium alloys display even greater performance than bulk equivalents. Increased thermoelectric efficiency of nanostructured materials have led to significant interests in developing thin film and nanowire structures. Here, we report on the first successful electrodeposition of lanthanum telluride thin films and nanowires. The electrodeposition of lanthanum telluride thin films is performed in ionic liquids at room temperature. The synthesis of nanowires involves electrodepositing lanthanum telluride arrays into anodic aluminum oxide (AAO) nanoporous membranes. These novel procedures can serve as an alternative means of simple, inexpensive and laboratory-environment friendly methods to synthesize nanostructured thermoelectric materials. The thermoelectric properties of thin films and nanowires will be presented to compare to current state-of-the-art thermoelectric materials. The morphologies and chemical compositions of the deposited films and nanowires are characterized using SEM and EDAX analysis.

  5. Dislocation emission from a thin-film-covered crack

    SciTech Connect

    Zhang, T.Y.; Qian, C.F.; Wang, T.; Tong, P. [Hong Kong Univ. of Science and Technology, Kowloon (Hong Kong). Dept. of Mechanical Engineering

    1999-08-01

    The present work investigates the effects of a passive film formed during stress corrosion cracking on ductile/brittle fracture behavior, considering the interaction of a dislocation with a thin-film-covered crack under an applied remote load. The dislocation emission from the thin-film-covered crack tip is analyzed, on the basis of the two-dimensional Rice-Thomson model, for screw and edge dislocations. The results show that the nominally critical stress intensity factor for dislocation emission is related to the thin film thickness, the properties of the film and the loading conditions. For a given loading mode and a given crack length, these exists a critical value of the film thickness at which the film does not influence the dislocation emission. When the film thickness is smaller than the critical value, a harder thin film makes the dislocation emission easier and a softer film makes the dislocation emission more difficult. The opposite is also true if the film thickness is larger than the critical value.

  6. Nanoscale Thin Film Electrolytes for Clean Energy Applications

    SciTech Connect

    Nandasiri, Manjula I.; Sanghavi, Rahul P.; Kuchibhatla, Satyanarayana V N T; Thevuthasan, Suntharampillai

    2012-02-01

    Ceria and zirconia based systems can be used as electrolytes to develop solid oxide fuel cells for clean energy production and to prevent air pollution by developing efficient, reliable oxygen sensors. In this study, we have used oxygen plasma assisted molecular beam epitaxy (OPA-MBE) to grow samaria doped ceria (SDC), to understand the role of dopant concentration and geometry of the films towards the ionic conduction in these thin films. We have also discussed the Gd doped CeO2 (GDC) and Gd stabilized ZrO2 (GSZ) multi-layer thin films to investigate the effect of interfacial phenomena on the ionic conductivity of these hetero-structures. We found the optimum concentration to be 15 mol % SmO1.5, for achieving lowest electrical resistance in SDC thin films. The electrical resistance decreases with the increase in film thickness up to 200 nm. The results demonstrate the usefulness of this study towards establishing an optimum dopant concentration and choosing an appropriate thin film thickness to ameliorate the conductance of the SDC material system. Furthermore, we have explored the conductivity of highly oriented GDC and GSZ multi-layer thin films, wherein the conductivity increased with an increase in the number of layers. The extended defects and lattice strain near the interfaces increase the density of oxygen vacancies, which leads to enhanced ionic conductivity in multi-layer thin films.

  7. Mounted nanoporous anodic alumina thin films as planar optical waveguides.

    PubMed

    Lazzara, Thomas D; Lau, K H Aaron; Knoll, Wolfgang

    2010-07-01

    Solid-supported thin films of self-organized nanoporous anodic aluminum oxide (AAO) have been widely employed for the template preparation of nanostructured functional materials. Recently, the use of nanoporous AAO thin films in optical waveguide spectroscopy (OWS) has been explored for high sensitivity, in situ monitoring of processes occurring within these nanoporous templates. In this contribution, we demonstrate a strategy for mounting bulk anodized AAO thin films on heterogeneous solid-supports suitable for waveguide sensing experiments. Unlike conventional preparations of AAO thin films by anodization of vacuum- or electrochemically deposited Al thin films, the full range of techniques available to anodize bulk Al may potentially be applied with the present method. Moreover, we show that AAO thin films mounted on glass substrates can have superior waveguide coupling properties compared to conventionally prepared samples. The nanostructure of the AAO can be well characterized by an EMT-OWS analysis, demonstrated by comparing scanning electron microscopy images of the AAO and the pore dimensions calculated from an effective medium theory (EMT) analysis of the film refractive index measured by OWS. Finally, using a curved metallic substrate as an example, we show that our mounting technique can be used as a general strategy to functionalize objects with nanoporous AAO films. PMID:21128414

  8. Integration of thin film decoupling capacitors

    SciTech Connect

    Garino, T.; Dimos, D.; Lockwood, S.

    1994-10-01

    Thin film decoupling capacitors consisting of submicron thick, sol-gel Pb(Zr,Ti)O{sub 3} layers between Pt electrodes on a Si substrate have recently been developed. Because the capacitor structure needs to be only {approximately}3 {mu}m thick, these devices offer advantages such as decreased package volume and ability to integrate so that interconnect inductance is decreased, which allows faster IC processing rates. To fully utilize these devices, techniques of integrating them onto packages such as multi-chip modules and printed wiring boards or onto IC dies must be developed. The results of our efforts at developing integration processes for these capacitors are described here. Specifically, we have demonstrated a process for printing solder on the devices at the Si wafer level and reflowing it to form bumps and have developed a process for fabricating the devices on thin (25 to 75 {mu}m) substrates to facilitate integration onto ICs and printed wiring boards. Finally, we assessed the feasibility of fabricating the devices on rough surfaces to determine whether it would be possible to fabricate these capacitors directly on multi-layer ceramic substrates.

  9. Fabrication of Thin Film Heat Flux Sensors

    NASA Technical Reports Server (NTRS)

    Will, Herbert A.

    1992-01-01

    Prototype thin film heat flux sensors have been constructed and tested. The sensors can be applied to propulsion system materials and components. The sensors can provide steady state and fast transient heat flux information. Fabrication of the sensor does not require any matching of the mounting surface. Heat flux is proportional to the temperature difference across the upper and lower surfaces of an insulation material. The sensor consists of an array of thermocouples on the upper and lower surfaces of a thin insulating layer. The thermocouples for the sensor are connected in a thermopile arrangement. A 100 thermocouple pair heat flux sensor has been fabricated on silicon wafers. The sensor produced an output voltage of 200-400 microvolts when exposed to a hot air heat gun. A 20 element thermocouple pair heat flux sensor has been fabricated on aluminum oxide sheet. Thermocouples are Pt-Pt/Rh with silicon dioxide as the insulating material. This sensor produced an output of 28 microvolts when exposed to the radiation of a furnace operating at 1000 C. Work is also underway to put this type of heat flux sensor on metal surfaces.

  10. Mechanics of evolving thin film structures

    NASA Astrophysics Data System (ADS)

    Liang, Jim

    In the Stranski-Krastanov system, the lattice mismatch between the film and the substrate causes the film to break into islands. During annealing, both the surface energy and the elastic energy drive the islands to coarsen. Motivated by several related studies, we suggest that stable islands should form when a stiff ceiling is placed at a small gap above the film. We show that the role of elasticity is reversed: with the ceiling, the total elastic energy stored in the system increases as the islands coarsen laterally. Consequently, the islands select an equilibrium size to minimize the combined elastic energy and surface energy. In lithographically-induced self-assembly, when a two-phase fluid confined between parallel substrates is subjected to an electric field, one phase can self-assemble into a triangular lattice of islands in another phase. We describe a theory of the stability of the island lattice. The islands select the equilibrium diameter to minimize the combined interface energy and electrostatic energy. Furthermore, we study compressed SiGe thin film islands fabricated on a glass layer, which itself lies on a silicon wafer. Upon annealing, the glass flows, and the islands relax. A small island relaxes by in-plane expansion. A large island, however, wrinkles at the center before the in-plane relaxation arrives. The wrinkles may cause significant tensile stress in the island, leading to fracture. We model the island by the von Karman plate theory and the glass layer by the Reynolds lubrication theory. Numerical simulations evolve the in-plane expansion and the wrinkles simultaneously. We determine the critical island size, below which in-plane expansion prevails over wrinkling. Finally, in devices that integrate dissimilar materials in small dimensions, crack extension in one material often accompanies inelastic deformation in another. We analyze a channel crack advancing in an elastic film under tension, while an underlayer creeps. We use a two-dimensional shear lag model to approximate the three-dimensional fracture process. Based on the computational results, we propose new experiments to measure fracture toughness and creep laws in small structures. Similarly, we study delayed crack initiation, steady crack growth, and transient crack growth when the underlayer is viscoelastic.

  11. Hafnia: Energetics of Thin Films and Nanoparticles

    SciTech Connect

    Zhou, W.; Ushakov, S; Wang, T; Ekerdt, J; Demkov, A; Navrotsky, A

    2010-01-01

    Crystallization energetics of amorphous hafnia powders and thin films on platinum substrates was studied by differential scanning calorimetry and time-resolved high temperature x-ray diffraction. For initially amorphous 25 and 20 nm films from atomic layer deposition, crystallization enthalpy decreases from -38 to -32 kJ/mol, and crystallization temperature increases from 388 to 417 C as thickness decreases. Enthalpy of water vapor adsorption on the surface of monoclinic hafnia was measured for both bulk powder and nanoparticles and was found to vary from -110 to -130 kJ/mol for coverage of -5 H{sub 2}O/nm{sup 2}. The enthalpies of monoclinic hafnia with various surface areas, prepared by crystallization and annealing of an amorphous hafnia precursor, were measured by high temperature oxide melt solution calorimetry. Under the previously used assumption that the interfacial enthalpy is 20% of the surface enthalpy, the surface enthalpy was calculated from experimental data as 2.8 {+-} 0.1 J/m{sup 2} for the hydrated surface and 3.7 {+-} 0.1 J/m{sup 2} for the anhydrous hafnia surface. These values are similar to those measured previously for monoclinic zirconia.

  12. Transparent conducting thin films for spacecraft applications

    NASA Technical Reports Server (NTRS)

    Perez-Davis, Marla E.; Malave-Sanabria, Tania; Hambourger, Paul; Rutledge, Sharon K.; Roig, David; Degroh, Kim K.; Hung, Ching-Cheh

    1994-01-01

    Transparent conductive thin films are required for a variety of optoelectronic applications: automotive and aircraft windows, and solar cells for space applications. Transparent conductive coatings of indium-tin-oxide (ITO)-magnesium fluoride (MgF2) and aluminum doped zinc oxide (AZO) at several dopant levels are investigated for electrical resistivity (sheet resistance), carrier concentration, optical properties, and atomic oxygen durability. The sheet resistance values of ITO-MgF2 range from 10(exp 2) to 10(exp 11) ohms/square, with transmittance of 75 to 86 percent. The AZO films sheet resistances range from 10(exp 7) to 10(exp 11) ohms/square with transmittances from 84 to 91 percent. It was found that in general, with respect to the optical properties, the zinc oxide (ZnO), AZO, and the high MgF2 content ITO-MgF2 samples, were all durable to atomic oxygen plasma, while the low MgF2 content of ITO-MgF2 samples were not durable to atomic oxygen plasma exposure.

  13. Control of thin film processing behavior through precursor structural modifications

    SciTech Connect

    Schwartz, R.W.; Voigt, J.A.; Boyle, T.J.; Christenson, T.A.; Buchheit, C.D. [Sandia National Labs., Albuquerque, NM (United States). Advanced Materials Lab.

    1995-02-01

    In the sol-gel processing of ceramic thin films it has been frequently noted that the processing behavior, microstructure and properties of the films are dependent on the nature of the coating solution. In an attempt to understand such thin film processing-property relationships, the authors have systematically investigated the effects of varying the precursor nature on thin film densification and crystallization for ZrO{sub 2} and TiO{sub 2} films. Metal alkoxide starting compounds, e.g., zirconium n-butoxide{center_dot}n-butanol and titanium i-propoxide, were reacted with acetic acid and 2,4-pentanedione to prepare coating solutions for thin film deposition. The use of these chelating ligands resulted in solution oligomeric species of different nature. Studies of thin film processing indicated that film processing characteristics, i.e., consolidation, densification and crystallization, were strongly dependent on solution precursor nature. Ligand steric size, pyrolysis behavior, extent of chelation, and precursor reactivity were found to be key variables in controlling film processing characteristics.

  14. Platinum thin film resistors as accurate and stable temperature sensors

    Microsoft Academic Search

    W. Diehl

    1984-01-01

    The measurement characteristics of thin-Pt-film temperature sensors fabricated using advanced methods are discussed. The limitations of wound-wire Pt temperature sensors and the history of Pt-film development are outlined, and the commonly used film-deposition, structuring, and trimming methods are presented in a table. The development of a family of sputtered film resistors is described in detail and illustrated with photographs of

  15. Investigation of heteroepitaxial growth of magnetite thin films

    Microsoft Academic Search

    G. E. Sterbinsky; J. Cheng; P. T. Chiu; B. W. Wessels; D. J. Keavney

    2007-01-01

    Epitaxial magnetite (FeO) thin films were deposited by molecular beam epitaxy using molecular oxygen as the oxidant. Films deposited on (001) SrTiO, (001) MgO, and (001) BaTiO surfaces are epitaxial with the film (001) parallel to the substrate (001) and the film <100> parallel to the substrate <100>. X-ray magnetic circular dichroism was used to determine the relative Fe{sup 2+}\\/Fe{sup

  16. Interferometric measurement method of thin film thickness based on FFT

    NASA Astrophysics Data System (ADS)

    Shuai, Gaolong; Su, Junhong; Yang, Lihong; Xu, Junqi

    2009-05-01

    The kernel of modern interferometry is to obtain necessary surface shape and parameter by processing interferogram with reasonable algorithm. The paper studies the basic principle of interferometry involving 2-D FFT, proposes a new method for measuring thin film thickness based on FFT: by CCD receiving and acquired card collecting with the help of Twyman-Green interferometer, can a fringe interferogram of the measured thin film be obtained. Based on the interferogram processing knowledge, an algorithm processing software/program can be prepared to realize identification of the edge films, regional extension, filtering, unwrapping the wrapped phase etc. And in this way can the distribution of film information-coated surface be obtained and the thickness of thin film samples automatically measured. The findings indicate the PV value and RMS value of the measured film samples are 0.256 ? and 0.068 ? respectively and prove the new method has high precision.

  17. Growth of high Tc superconducting thin films for microwave applications

    SciTech Connect

    Wu, X.D.; Foltyn, S.R.; Muenchausen, R.E.; Dye, R.C.; Cooke, D.W.; Rollett, A.D.; Garcia, A.R.; Nogar, N.S. (Los Alamos National Lab., NM (USA)); Pique, A.; Edwards, R. (Neocera, New Brunswick, NJ (USA))

    1991-01-01

    High-{Tc} superconducting thin films of YBa{sub 2}Cu{sub 3}O{sub 7 {minus}{delta}} (YBCO) were deposited on sapphire substrates with buffer layers of yttria-stabilized zirconia and cerium oxide by using pulsed laser deposition (PLD) technique. The epitaxial relationship between the substrate and buffer layers as well as the buffer layer and the superconducting film was established. Furthermore, using the same thin film technique, YBCO superconducting thin films were deposited on both sides of substrates of up to 5 cm in diameter. The superconducting properties of the films on both the sapphire with buffer layers and large-area substrates were comparable to the ones of the best YBCO films. 8 refs., 6 figs.

  18. The state of the art of thin-film photovoltaics

    SciTech Connect

    Surek, T.

    1993-10-01

    Thin-film photovoltaic technologies, based on materials such as amorphous or polycrystalline silicon, copper indium diselenide, cadmium telluride, and gallium arsenide, offer the potential for significantly reducing the cost of electricity generated by photovoltaics. The significant progress in the technologies, from the laboratory to the marketplace, is reviewed. The common concerns and questions raised about thin films are addressed. Based on the progress to date and the potential of these technologies, along with continuing investments by the private sector to commercialize the technologies, one can conclude that thin-film PV will provide a competitive alternative for large-scale power generation in the future.

  19. Development of Thin Film Ceramic Thermocouples for High Temperature Environments

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Fralick, Gustave C.; Farmer, Serene C.; Sayir, Ali; Blaha, Charles A.; Gonzalez, Jose M.

    2004-01-01

    The maximum use temperature of noble metal thin film thermocouples of 1100 C (2000 F) may not be adequate for use on components in the increasingly harsh conditions of advanced aircraft and next generation launch technology. Ceramic-based thermocouples are known for their high stability and robustness at temperatures exceeding 1500 C, but are typically found in the form of rods or probes. NASA Glenn Research Center is investigating the feasibility of ceramics as thin film thermocouples for extremely high temperature applications to take advantage of the stability and robustness of ceramics and the non-intrusiveness of thin films. This paper will discuss the current state of development in this effort.

  20. The state of the art of thin-film photovoltaics

    SciTech Connect

    Surek, T. [National Renewable Energy Lab., Golden, CO (United States)

    1993-11-01

    Thin-film photovoltaic technologies, based on materials such as amorphous or polycrystalline silicon, copper indium diselenide, cadmium telluride, and gallium arsenide, offer the potential for significantly reducing the cost of electricity generated by photovoltaics. The significant progress in the technologies, from the laboratory to the marketplace, is reviewed. The common concerns and questions raised about thin films are addressed. Based on the progress to date and the potential of these technologies, along with continuing investments by the private sector to commercialize the technologies, one can conclude that thin-film PV will provide a competitive alternative for large-scale power generation in the future.

  1. Mechanics of precisely controlled thin film buckling on Elastomeric substrate.

    SciTech Connect

    Sun, Y.; Jiang, H.; Rogers, J.; Huang, Y.; Arizone State Univ.; Beckman Inst.; University of Illinois Urbana-Champaign

    2007-01-01

    Stretchable electronics has many important and emerging applications. Sun et al. [Nature Nanotech. 1, 201 (2006)] recently demonstrated stretchable electronics based on precisely controlled buckle geometries in GaAs and Si nanoribbons on elastomeric substrates. A nonlinear buckling model is presented in this letter to study the mechanics of this type of thin film/substrate system. An analytical solution is obtained for the buckling geometry (wavelength and amplitude) and the maximum strain in buckled thin film. This solution agrees very well with the experiments, and shows explicitly how buckling can significantly reduce the thin film strain to achieve the system stretchability.

  2. Sol-gel technology for ferroelectric thin films

    SciTech Connect

    Kim, You Song [Research Institute of Industrial Science and Technology, Pohang (Korea, Democratic People`s Republic of); Jang, Hyun M. [Pohang Univ. of Science and Technology (Korea, Democratic People`s Republic of)

    1994-12-31

    Sol-gel-derived ferroelectric thin films can offer particular promise for various microelectronic applications, including FRAM, DRAM elements, thin-film capacitors and pyroelectric IR sensors. In this article, recent progress in the sol-gel processing of two typical ferroelectric thin-film systems is briefly reviewed. These are lead zirconate titanate (PZT) solid solution and Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-based relaxor ferroelectrics. Several examples of the sol chemistry-structures/ferroelectric properties relationships are illustrated using various recent data, including results from the authors` laboratory.

  3. Synthesis Of Graphene/Chitosan Nanocomposite Thin Films

    NASA Astrophysics Data System (ADS)

    Ganesh, S.; Arockiadoss; Ramaprabhu, S.

    2010-10-01

    In this paper, we propose a cost-efficient thin film synthesis of the nanocomposite of Graphene and Chitosan using solution casting technique. Characterizations of the thin films clearly indicate the presence of dispersed flakes of Graphene in Chitosan. Spectroscopic studies reveal the presence of nanoparticles of Carbon in the composite though they also indicate presence of Oxygen which transcend from the bulk Graphite crystals. Preliminary amperometric studies reveal an increase in current with absorption of moisture and a potential humidity sensing ability of the nanocomposite thin film.

  4. Thermoelastic response of thin metal films and their adjacent materials

    SciTech Connect

    Kang, S.; Yoon, Y.; Kim, J.; Kim, W. [Samsung Electronics Co., Yongin-Si, 446-712 Gyeonggi-do (Korea, Republic of)] [Samsung Electronics Co., Yongin-Si, 446-712 Gyeonggi-do (Korea, Republic of)

    2013-01-14

    A pulsed laser beam applied to a thin metal film is capable of launching an acoustic wave due to thermal expansion. Heat transfer from the thin metal film to adjacent materials can also induce thermal expansion; thus, the properties of these adjacent materials (as well as the thin metal film) should be considered for a complete description of the thermoelastic response. Here, we show that adjacent materials with a small specific heat and large thermal expansion coefficient can generate an enhanced acoustic wave and we demonstrate a three-fold increase in the peak pressure of the generated acoustic wave on substitution of parylene for polydimethylsiloxane.

  5. A new radiative heater for high Tc thin film growth

    NASA Astrophysics Data System (ADS)

    Badaye, M.; Gardner, M.; Wong, A.; Dosanjh, P.; Bonn, D.; Hardy, W. N.

    1998-09-01

    The design of a new radiative heater for the growth of oxide thin films is presented. A blackbody cavity approach has been used to eliminate the large temperature variations usually observed during the growth of high Tc (HTC) superconducting thin films. Results show that this simple and inexpensive design enables one to work without the need for in situ monitoring and constant adjustment of the substrate temperature. The performance of the new heater is demonstrated by the growth of excellent quality HTC thin films.

  6. Angular magnetoresistance in semiconducting undoped amorphous carbon thin films

    NASA Astrophysics Data System (ADS)

    Sagar, Rizwan Ur Rehman; Saleemi, Awais Siddique; Zhang, Xiaozhong

    2015-05-01

    Thin films of undoped amorphous carbon thin film were fabricated by using Chemical Vapor Deposition and their structure was investigated by using High Resolution Transmission Electron Microscopy and Raman Spectroscopy. Angular magnetoresistance (MR) has been observed for the first time in these undoped amorphous carbon thin films in temperature range of 2 ˜ 40 K. The maximum magnitude of angular MR was in the range of 9.5% ˜ 1.5% in 2 ˜ 40 K. The origin of this angular MR was also discussed.

  7. A Free Energy Model for Thin-film Shape Memory Alloys Jordan E. Massad*1

    E-print Network

    A Free Energy Model for Thin-film Shape Memory Alloys Jordan E. Massad*1 , Ralph C. Smith1 and Greg Mechanical & Aerospace Engineering Dept., UCLA, Los Angeles, CA 90095 ABSTRACT Thin-film shape memory alloys comparison with thin-film NiTi superelastic hysteresis data. Keywords: Shape memory alloy model; thin film

  8. Magnesium diboride thin films and devices

    Microsoft Academic Search

    Yi Cui

    2007-01-01

    Magnesium diboride (MgB2) is a binary compound superconductor with a superconducting transition temperature Tc of ˜40 K. MgB2 has two conduction bands: a two-dimensional sigma band and a three-dimensional pi band with weak interband scattering. The two gap superconductivity in MgB2 gives rise to many interesting physical properties not possible in other superconductors. The relatively high Tc combined with phonon

  9. Robust topological surface state in Kondo insulator SmB6 thin films

    NASA Astrophysics Data System (ADS)

    Yong, Jie; Jiang, Yeping; Usanmaz, Demet; Curtarolo, Stefano; Zhang, Xiaohang; Li, Linze; Pan, Xiaoqing; Shin, Jongmoon; Takeuchi, Ichiro; Greene, Richard L.

    2014-12-01

    Fabrication of smooth thin films of topological insulators with true insulating bulk are extremely important for utilizing their novel properties in quantum and spintronic devices. Here, we report the growth of crystalline thin films of SmB6, a topological Kondo insulator with true insulating bulk, by co-sputtering both SmB6 and B targets. X-ray diffraction, Raman spectroscopy, and transmission electron microscopy indicate films that are polycrystalline with a (001) preferred orientation. When cooling down, resistivity ? shows an increase around 50 K and saturation below 10 K, consistent with the opening of the hybridization gap and surface dominated transport, respectively. The ratio ?2K/?300K is only about two, much smaller than that of bulk, which indicates a much larger surface-to-bulk ratio. Point contact spectroscopy using a superconductor tip on SmB6 films shows both a Kondo Fano resonance and Andeev reflection, indicating an insulating Kondo lattice with metallic surface states.

  10. Analytical and numerical modeling of surface morphologies in thin films

    SciTech Connect

    Genin, F.Y.

    1995-05-01

    Experimental studies have show that strains due to thermal expansion mismatch between a film and its substrate can produce very large stresses in the film that can lead to the formation of holes and hillocks. Based on a phenomenological description of the evolution of a solid surface under both capillary and stress driving forces and for surface and grain boundary self-diffusion, this article provides analytical and numerical solutions for surface profiles of model geometries in polycrystalline thin films. Results can explain a variety of surface morphologies commonly observed experimentally and are discussed to give some practical insights on how to control the growth of holes and hillocks in thin films.

  11. Profile measurements of thin liquid films using reflectometry

    NASA Astrophysics Data System (ADS)

    Hanchak, M. S.; Vangsness, M. D.; Byrd, L. W.; Ervin, J. S.; Jones, J. G.

    2013-11-01

    Microscope-based reflectometry was used to measure the thickness profile of thin films of n-octane on silicon wafer substrates. Coupled with micro-positioning motorized stages and custom software, two-dimensional profiles of the film thickness from the adsorbed film (˜10 nm) to the intrinsic meniscus (˜1000 nm) were automatically and repeatedly measured. The reflectometer aperture was modified to provide better spatial resolution in areas of high curvature, the transition region, where evaporative flux is at a maximum. This technique will provide data for the validation of both existing and future models of thin film evaporation.

  12. Strain Relaxation and Vacancy Creation in Thin Platinum Films

    SciTech Connect

    Gruber, W.; Chakravarty, S.; Schmidt, H. [Technische Universitaet Clausthal, Institut fuer Metallurgie, Clausthal-Zellerfeld (Germany); Baehtz, C. [Helmholtz Zentrum Dresden Rossendorf, Institute of Ion Beam Physics and Materials Research, Dresden (Germany); Leitenberger, W. [Universitaet Potsdam, Institut fuer Physik und Astronomie, Potsdam (Germany); Bruns, M. [Karlsruher Institut fuer Technologie, Institute for Applied Materials, Eggenstein-Leopoldshafen (Germany); Karlsruher Institut fuer Technologie, Karlsruher Micro Nano Facility, Eggenstein-Leopoldshafen (Germany); Kobler, A.; Kuebel, C. [Karlsruher Institut fuer Technologie, Institute of Nanotechnology, Eggenstein-Leopoldshafen (Germany); Karlsruher Institut fuer Technologie, Karlsruher Micro Nano Facility, Eggenstein-Leopoldshafen (Germany)

    2011-12-23

    Synchrotron based combined in situ x-ray diffractometry and reflectometry is used to investigate the role of vacancies for the relaxation of residual stress in thin metallic Pt films. From the experimentally determined relative changes of the lattice parameter a and of the film thickness L the modification of vacancy concentration and residual strain was derived as a function of annealing time at 130 deg. C. The results indicate that relaxation of strain resulting from compressive stress is accompanied by the creation of vacancies at the free film surface. This proves experimentally the postulated dominant role of vacancies for stress relaxation in thin metal films close to room temperature.

  13. Spectrum method for laser induced damage in dielectric thin films

    NASA Astrophysics Data System (ADS)

    Cai, Yue; Zhou, Meng-lian; Ma, Zhi-liang; Wang, Li-jun

    2015-05-01

    This paper shows some tentative results with which laser induced damage on dielectric thin films is analyzed by using the transmission spectrum. The damage characters were extracted in high-resolution images of damaged films, and transmission spectrum of damaged thin films was measured. The mathematical model of transmission was built based on the matrix optics theory with the optical properties, which include the effective refractive index, effective extinction coefficient, effective thickness and wavelength, and so on. Changes of optical properties in different damaged degree were analyzed by the transmittance spectrum. Through which laser-induced damage mechanisms had been analyzed with the micro-examinations of films.

  14. Sensing Arrays Constructed from Nanoparticle Thin Films and Interdigitated Microelectrodes

    PubMed Central

    Wang, Lingyan; Kariuki, Nancy N.; Schadt, Mark; Mott, Derrick; Luo, Jin; Zhong, Chuan-Jian; Shi, Xiajing; Zhang, Chen; Hao, Weibing; Lu, Susan; Kim, Nam; Wang, Jian-Q.

    2006-01-01

    This paper describes the results of a study of a few design parameters influencing the performance of sensor arrays constructed from nanostructured thin films and interdigitated microelectrodes (IMEs). The nanostructured thin films on the IME devices were prepared from nonanedithiol (NDT) and mercaptoundecanoic acid (MUA) linked assemblies of 2-nm sized gold nanoparticles. The sensor array data in response to volatile organic compounds were collected and analyzed using fractional factorial experimental design and analysis of variance for understanding effects of the design parameters on the sensitivity. While the smaller value for the microelectrode space, width, and length generally led to higher response sensitivity, a strong dependence on the nature of the nanostructured thin films was found. The microelectrode space was the most important design parameter for NDT-based thin films. However, the microelectrode space, width, and length were found to play almost equally important roles for MUA-based thin films. The principal component analysis results for classification performances of the arrays consisting of a set of thin films have demonstrated the possibility of optimizing sensor arrays by appropriate selections of microelectrode parameters and nanostructured sensing films.

  15. Optical properties of amorphous ZnO thin film prepared from boiled Zn thin film in ultra high pure water

    NASA Astrophysics Data System (ADS)

    Subramania, S.; Devarajan, M.

    2012-06-01

    Amorphous zinc oxide (a-ZnO) thin films were synthesized from RF sputtered Zn thin films. The conversion was performed by processing Zn thin film in ultra high pure water at 95°C in various process times (120-180 min). X-ray spectra revealed the presence of amorphous ZnO in the processed films. The calculated band gap was laid in between 3.25 and 3.2 eV. Non-linear behavior in I-V characteristics was observed for all films. The structural defects of a-ZnO were confirmed with PL and Raman studies. The synthesized films at 180 min were more oxygen deficient.

  16. Direct Patterning of Silicon Nitride Thin Film by Projection Photoablation for Fabricating Thin-Film Transistor Liquid Crystal Displays

    NASA Astrophysics Data System (ADS)

    Chen, Chao-Nan; Wu, Gwo-Mei; Feng, Wu-Shiung; Jean, Hao-Wen

    2008-04-01

    The direct patterning of silicon nitride (SiNx) thin films on glass substrates using a KrF 248 nm excimer laser has been investigated. The direct laser patterning process offers a cost-effective alternative to wet- and dry-etch lithographies for the fabrication of thin-film transistor liquid crystal displays (TFT-LCDs). It is demonstrated that direct laser patterning can effectively pattern 200 nm SiNx thin films at the laser energy density of 1350 mJ/cm2. We can therefore reduce the cost and process time by using excimer laser patterning and eliminating the need for wet- and dry-etch processes.

  17. Developing Multilayer Thin Film Strain Sensors With High Thermal Stability

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Fralick, Gustave C.; Gonzalez, Jose M., III

    2006-01-01

    A multilayer thin film strain sensor for large temperature range use is under development using a reactively-sputtered process. The sensor is capable of being fabricated in fine line widths utilizing the sacrificial-layer lift-off process that is used for micro-fabricated noble-metal sensors. Tantalum nitride films were optimized using reactive sputtering with an unbalanced magnetron source. A first approximation model of multilayer resistance and temperature coefficient of resistance was used to set the film thicknesses in the multilayer film sensor. Two multifunctional sensors were fabricated using multilayered films of tantalum nitride and palladium chromium, and tested for low temperature resistivity, TCR and strain response. The low temperature coefficient of resistance of the films will result in improved stability in thin film sensors for low to high temperature use.

  18. Wrinkling of Thin Films Induced by Viscous Stress

    NASA Astrophysics Data System (ADS)

    Chatterjee, Sourav; McDonald, Christina; Niu, Jiani; Huang, Rui; Velankar, Sachin

    2013-11-01

    Compression of thin films attached to compliant solid substrates can induce a variety of highly ordered and complex wrinkling patterns. We study an analogous problem of the wrinkling instability of a thin film floating on a viscous fluid. Uniaxial compression of the fluid induces a viscous stress which leads to the wrinkling of the film. We experimentally determine the effect of geometry and material properties on the wrinkle wavelength. A shear lag approach is used to determine the stress distribution prior to buckling. A linear stability analysis of the film under this stress distribution is used to determine the maximally growing wavelength in the system. Both experiments as well as stability analysis show that the wavelength depends significantly on film length and the ratio of the film and fluid layer thickness. Most importantly, unlike previous research on fluid-supported films, the wrinkle wavelength is rate-dependent, and reduces with increasing compression rate.

  19. Microstructural Characterization of Thin Polyimide Films by Positron Lifetime Spectroscopy

    NASA Technical Reports Server (NTRS)

    Eftekhari, A.; St.Clair, A. K.; Stoakley, D. M.; Sprinkle, Danny R.; Singh, J. J.

    1996-01-01

    Positron lifetimes have been measured in a series of thin aromatic polyimide films. No evidence of positronium formation was observed in any of the films investigated. All test films exhibited only two positron lifetime components, the longer component corresponding to the positrons annihilating at shallow traps. Based on these trapped positron lifetimes, free volume fractions have been calculated for all the films tested. A free volume model has been developed to calculate the dielectric constants of thin polyimide films. The experimental and the calculated values for the dielectric constants of the films tested are in reasonably good agreement. It has been further noted that the presence of bulky CF(sub 3) groups and meta linkages in the polyimide structure results in higher free volume fraction and, consequently, lower dielectric constant values for the films studied.

  20. TI--CR--AL--O thin film resistors

    DOEpatents

    Jankowski, Alan F. (Livermore, CA); Schmid, Anthony P. (Solana Beach, CA)

    2000-01-01

    Thin films of Ti--Cr--Al--O are used as a resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O.sub.2. Resistivity values from 10.sup.4 to 10.sup.10 Ohm-cm have been measured for Ti--Cr--Al--O film <1 .mu.m thick. The film resistivity can be discretely selected through control of the target composition and the deposition parameters. The application of Ti--Cr--Al--O as a thin film resistor has been found to be thermodynamically stable, unlike other metal-oxide films. The Ti--Cr--Al--O film can be used as a vertical or lateral resistor, for example, as a layer beneath a field emission cathode in a flat panel display; or used to control surface emissivity, for example, as a coating on an insulating material such as vertical wall supports in flat panel displays.